EP4598585A1 - Product - Google Patents

Product

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Publication number
EP4598585A1
EP4598585A1 EP23793011.0A EP23793011A EP4598585A1 EP 4598585 A1 EP4598585 A1 EP 4598585A1 EP 23793011 A EP23793011 A EP 23793011A EP 4598585 A1 EP4598585 A1 EP 4598585A1
Authority
EP
European Patent Office
Prior art keywords
antimicrobial
antibody
microbe
antimicrobial agent
moiety
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23793011.0A
Other languages
German (de)
French (fr)
Inventor
Christoph Tang
Hayley LAVENDER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oxford University Innovation Ltd
Original Assignee
Oxford University Innovation Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oxford University Innovation Ltd filed Critical Oxford University Innovation Ltd
Publication of EP4598585A1 publication Critical patent/EP4598585A1/en
Pending legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/62—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being a protein, peptide or polyamino acid
    • A61K47/65—Peptidic linkers, binders or spacers, e.g. peptidic enzyme-labile linkers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
    • A61K47/6835—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/04—Antibacterial agents

Definitions

  • the invention relates to antimicrobials, and methods and uses thereof.
  • the agents of the invention are particularly useful in treating infections by pathogenic bacteria such as N. gonorrhoeae.
  • Antimicrobials such as antimicrobial peptides (AMPs)
  • AMPs antimicrobial peptides
  • the non-specificity of AMPs combined with the potential toxic side effects, such as haemolytic activity, hamper their clinical development.
  • Neisseria gonorrhoeae is a Gram negative; obligate human pathogen, which is the causative agent of the sexually transmitted infection gonorrhoea.
  • N. gonorrhoeae has developed mechanisms to avoid host-mediated innate immune defence and clinical isolates typically exhibit high levels of antimicrobial resistance such as azithromycin resistance. It is an object of the invention to identify further and improved antimicrobials, in particular against drug-resistant microbes, such as N. gonorrhoeae, for treating and preventing infections with reduced toxicity against host cells. Summary of the Invention The inventors have recognised the need to selectively kill pathogenic microbes such as pathogenic bacteria whilst minimising non-selective cell killing.
  • the agent is selective for the pathogenic microbe. As such, it can be used to treat infection by the pathogenic microbe whilst minimising side effects arising from off-target activity.
  • One pathogenic microbe of particular interest is the pathogenic bacteria N. gonorrhoeae.
  • the inventors have developed novel antimicrobials that specifically target N. gonorrhoeae, which are activated in the presence of the protease secreted by N. gonorrhoeae, immunoglobulin A1 proteases (IgAP).
  • IgAP immunoglobulin A1 proteases
  • the inventors generated an antibody-peptide conjugate (APC) consisting of an anti- N.
  • AMP antimicrobial peptide
  • Oct-TriA 1 modification of the C- terminus of Oct-TriA 1 with two IgAP cleavable linkers still displayed excellent antimicrobial activity but not when bound to the MtrE mAb.
  • Oct-TriA 1 was cleaved from the APC and displayed potent antimicrobial activity against multidrug resistant N. gonorrhoeae.
  • the linker is cleaved by the protease secreted by the microbe of interest, and the antimicrobial moiety is released from the microbe-targeting moiety and becomes active.
  • the invention is not however limited to treatment of infection by bacteria such as N. gonorrhoeae.
  • the invention provides a broader approach to treating infection by pathogenic microbes and is readily applied in treating a wide range of infections, with advantages as set out herein.
  • an antimicrobial agent comprising a) a microbe-targeting moiety; b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker.
  • the microbe expresses one or more proteins such as one or more proteases, and the linker is capable of being cleaved by said one or more proteins (e.g. proteases).
  • the antimicrobial moiety is an antibiotic compound e.g.
  • an antibiotic compound selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides.
  • the antimicrobial moiety is an N-acylated tridecapeptide or N-acylated tridecalipopeptide (e.g. TriA1), such as Oct-TriA1.
  • the microbe is a bacterium, such as a bacterium of family Neisseriaceae (e.g. Neisseria gonorrhoeae).
  • the microbe-targeting moiety is an antibody.
  • the antibody is capable of specifically binding to MtrE.
  • an antibody as described in more detail herein is also provided.
  • a combination of antibodies as described herein are also provided.
  • a method for producing an antibody as described herein Also provided is a pharmaceutical composition comprising the antimicrobial agent and/or the antibody provided herein..
  • an agent as described in more detail herein e.g. an antimicrobial agent as described herein or an antibody as described herein for use in medicine.
  • the agent may be for use in treating or preventing bacterial infection in a subject in need thereof.
  • protease-cleavable oligopeptide e.g. a linker
  • a kit comprising an antimicrobial agent or an antibody as provided herein, together with instructions for use.
  • a method of making an antimicrobial agent as described herein comprising conjugating an antimicrobial moiety to a microbe-targeting moiety (e.g. an antibody as described herein ) via a linker, wherein said linker is selectively cleavable by said microbe.
  • a protease-cleavable oligopeptide as described in more detail herein to conjugate a microbe-targeting moiety to an antimicrobial moiety. Also provided is a method of identifying the presence of bacteria (e.g. N. gonorrhoeae) or a protein or a protein fragment thereof, in a sample using said antibody.
  • bacteria e.g. N. gonorrhoeae
  • FIG. 3 Flow cytometry analysis of MtrE mAb (black) or APCs conjugated to PRN2028 (blue), PRN2029 (green) and PRN2208 (orange) binding to FA1090 (c), MS11 (d) and G97687 (e).
  • Figure 3 APC linker is cleaved in the presence of IgAP.
  • IgAP IgAP cleavage of hIgA1 in supernatant from WT MS11, FA1090, G97687 with isogenic ⁇ IgAP and ⁇ MtrE mutants.
  • hIgA1 incubated in GW media or PBS used as a negative control for cleavage.
  • OctTriA 1 analogues with IgAP linker Structure of OctTriA 1 analogues with IgAP linker, peptide number PRN2028 (a) and PRN2029 (b). Cleavage product indicated in red resulting in the liberated peptide PRN1967 and PRN1968 respectively. Spacer (blue) between antimicrobial OctTriA1 and IgAP linker. Mass spectrometry analysis of IgAP cleavage of peptides PRN2028 (c, box with solid line) and PRN2029 (d, box with solid line) to PRN1967 (c, box with dotted line) and PRN1968 (d, box with dotted line) after incubation in supernatant from WT MS11 but not in MS11 ⁇ IgAP supernatant.
  • Figure 7 APC linker is cleaved by FA1090 IgAP. Mass spectrometry analysis of released PRN1967 (a, blue peak) and PRN1968 (b, green peak) peptide from APC after incubation in supernatant from WT FA1090 but not in FA1090 ⁇ IgAP supernatant. PRN1968 and PRN1969 in PBS as well as supernatant from FA1090 and FA1090 ⁇ IgAP shown as a mass spectrometry controls.
  • Figure 8 OctTriA 1 analogues are bactericidal after cleavage by the IgAP from isolates with upregulated MtrE.
  • gonorrhoeae strains selected from a variety of core genome groups tested.
  • Recombinant MtrE along with WT gonococcal strains, FA1090 and MS11 with isogenic ⁇ MtrE used as mAb controls.
  • Figure 12 Western blot analysis of MtrE mAb binding to Neisseria meningitidis strains. Of note, mAb 184a-D10 does not cross react with N. meningitides. Recombinant MtrE was used as a mAb control.
  • Figure 13 Surface recognition of MtrE.
  • the microbe-targeting moiety may for example selectively target or bind to an epitope on the target microbe.
  • the epitope may be present or expressed on the surface of the target microbe.
  • the epitope may for example be a specific protein expressed by the target microbe on the surface of the target microbe.
  • the microbe-targeting moiety may for example be an antibody as described herein which selectively binds to the epitope on the target microbe.
  • the antimicrobial moiety can be any suitable agent which has antimicrobial activity.
  • the antimicrobial moiety is typically a chemical compound for example an antibiotic compound.
  • the antimicrobial moiety may be an oligopeptide or derivative thereof. Suitable antimicrobial moieties are described in more detailed herein.
  • the activity of the antimicrobial moiety is not limited in the invention, and any suitable antimicrobial moiety can be used.
  • the antimicrobial moiety is an antimicrobial peptide such as an antibiotic peptide.
  • the linker comprises an oligopeptide.
  • the antimicrobial peptide and the linker can thus be synthesized as a single moiety, e.g. via solid-phase peptide synthesis. Solid-phase peptide synthesis methods are well known by those of skill in the art and peptide-synthesis is commercially available as a service.
  • the invention is not limited to the use of peptide linkers and/or antimicrobial moieties.
  • the N.gonorrhoeae may be any strain, such as FA1090, FA19, MS11, F62, WHO-F (NCTC 13477), WHO-G (NCTC 13478), WHO-K (NCTC 13479), WHO-L (NCTC 13480), WHO-M (NCTC 13481), WHO-N (NCTC 13482), WHO-O (NCTC 13483), WHO-P (NCTC 13484), WHO-U (NCTC 13417), WHO-V (NCTC 13418), WHO-W (NCTC 13419), WHO-X (NCTC 13420), WHO-Y (NCTC 13421), or WHO-Z (NCTC 13411), or variants thereof.
  • the N.gonorrhoeae may be multidrug resistant.
  • the N.gonorrhoeae strain may not express functional PIA and/or PIB (encoded by PorA and PorB, respectively).
  • PIA and/or PIB may be absent, or the PorA and/or PorB genes may comprise one or more mutations.
  • the microbe-targeting moiety may be specific for any epitope in a target microbe.
  • the epitope may be in any protein specifically expressed in the target microbe.
  • the protein may be a surface protein.
  • the protein may be a lipopeptide.
  • the microbe- targeting moiety may be specific for NGO0901, NGO0439 (LolB), NGO2047, NGO0277 (ComL), NGO1780 (BamE), NGO2139 (MetQ), NGO0994 (Laz), NGO1225 (peptidyl- prolyl cis-trans isomerase), NGO1363 (MtrE), NGO1559 (OmpA), NGO1276 (AniA), NGO1393 (mafA2), or NGO1067 (mafA1).
  • the microbe-targeting moiety may be specific for MtrE.
  • HA-tag which correspond to amino acids 98 to 106 of human influenza hemagglutinin, polyhistidine (His), c-myc and FLAG.
  • the affinity tag may be fused to the N- or C-terminal of the microbe-targeting moiety, for example.
  • Antibody The invention also provides antibodies specific for N.gonorrhoeae. The antibody may be useful as the microbe-targeting moiety of the antimicrobial agent of the invention. Hence, the microbe-targeting moiety of the antimicrobial agent of the invention may comprise or consist of an antibody of the invention.
  • an antimicrobial agent of the invention may comprise a) an antibody specific for a microbe, b) a linker selectively cleavable by said microbe, and c) an antimicrobial moiety, wherein the microbe-targeting moiety is conjugated to the antibody by the linker.
  • the antibody may be capable of specifically binding to MtrE.
  • the anti-MtrE antibody may comprise at least three, four, five, or all six CDRs: CDRH1 (GFSLTRYGVH), CDRH2 (VIWSDGTTTYNSALKS), CDRH3 (GTSAYYGNNDAMVF), CDRL1 (LASGNIHNYLA), CDRL2 (NAKTLAD) and CDRL3 (QHFWTSPFT), as set out in SEQ ID NOs: 22-24 and 26-28, respectively (according to the KABAT numbering system).
  • the antibody may comprise at least one, at least two or all three heavy chain CDRs (CDRHs).
  • the antibody may comprise at least one, at least two or all three light chain CDRs (CDRLs).
  • the antibody typically comprises all six (i.e.
  • an antibody comprising these sequences is capable of specifically binding to MtrE in N.gonorrhoeae.
  • This antibody does not cross react with MtrE in N.meningitis.
  • an antibody of the invention may be capable of specifically binding to MtrE in N.gonorrhoeae.
  • the antibody of the invention may not cross react with MtrE in N.meningitis.
  • the antibody may comprise at least one, at least two or all three heavy chain CDRs (CDRHs).
  • the antibody may comprise at least one, at least two or all three light chain CDRs (CDRLs).
  • the antibody typically comprises all six (i.e. three heavy and three light chain) CDRs.
  • the antibody of the invention may comprise a heavy chain variable domain having an amino acid sequence with ⁇ 80%, ⁇ 90%, ⁇ 95%, ⁇ 96%, ⁇ 97%, ⁇ 98%, ⁇ 99% or 100% sequence identity to SEQ ID NO: 1 (EVQLVESGGGLVKPGGSLKLSCSASGFTFNDYYMYWVRQTPEKRLEWVATISYD GTDFYYPDSLKGRFTISRDNAKNNLYLQMSSLKSEDTAIYYCARGYYYDSSYFGV WGAGTTVTVSS), and/or a light chain variable domain having an amino acid sequence with ⁇ 80%, ⁇ 90%, ⁇ 95%, ⁇ 96%, ⁇ 97%, ⁇ 98%, ⁇ 99% or 100% sequence identity to SEQ ID NO: 5 (DIVMSQSPSSLAVSVGEKVTLSCKSSQSLLNSRTRKNYLTWYQQKPGQSPQLLIY WASTRESGVPDRFTGSGSGTDFTLTISSVQAEDLAVYYCK
  • an antibody comprising these sequences, mAb135a-D6, is capable of specifically binding to MtrE in N.gonorrhoeae or N. meningitis.
  • the term “antibody” referred to herein includes the various antibody formats disclosed herein, including those comprising various formats of heavy and/or light chains discussed herein.
  • the antibody may be selected from the group consisting of single chain antibodies, single chain variable fragments (scFvs), variable fragments (Fvs), fragment antigen- binding regions (Fabs), recombinant antibodies, monoclonal antibodies, fusion proteins comprising the antigen-binding domain of a native antibody or an aptamer, single-domain antibodies (sdAbs), also known as VHH antibodies, nanobodies (Camelid-derived single- domain antibodies), shark IgNAR-derived single-domain antibody fragments called VNAR, diabodies, triabodies, Anticalins, aptamers (DNA or RNA) and active components or fragments thereof.
  • scFvs single chain variable fragments
  • Fvs variable fragments
  • Fabs fragment antigen- binding regions
  • recombinant antibodies monoclonal antibodies, fusion proteins comprising the antigen-binding domain of a native antibody or an aptamer, single-domain antibodies (sdAbs), also known as VHH antibodies, nanobodies (
  • the antibody may comprise a complete antibody having full length heavy and light chains, or an antigen-binding fragment thereof.
  • the microbe-targeting moiety may be a full-length antibody.
  • the antibody may be an antigen-binding fragment.
  • An antigen-binding fragment of the invention binds to the same epitope of the parent antibody, i.e. the antibody from which the antigen-binding fragment is derived.
  • An antigen-binding fragment of the invention typically retains the parts of the parent antibody that interact with the epitope.
  • the antigen-binding fragment typically comprises the complementarity-determining regions (CDRs) that interact with the antigen, such as one, two, three, four, five or six CDRs.
  • the antigen-binding fragment further comprises the structural scaffold surrounding the CDRs of the parent antibody, such as the framework regions (e.g. FR1, 2, or 3) and/or the variable region domains of the heavy and/or light chains.
  • the antigen-binding fragment retains the same or similar binding affinity to the antigen as the parent antibody.
  • Antigen-binding fragments of antibodies include single chain antibodies (i.e.
  • the antibodies may be multi-valent, e.g. bivalent, trivalent or tetravalent.
  • Fully human antibodies are those antibodies in which the variable regions and the constant regions (where present) of both the heavy and the light chains are all of human origin, or substantially identical to sequences of human origin, but not necessarily from the same antibody.
  • the antibody binds to the epitope, e.g. in the with high affinity
  • an antibody of the invention may have an affinity constant (K D ) value for the MtrE of N. gonorrhoeae of ⁇ 100 ⁇ M, ⁇ 50 ⁇ M, ⁇ 25 ⁇ M, ⁇ 10 ⁇ M, ⁇ 1 ⁇ M, ⁇ 0.5 ⁇ M, or ⁇ 0.1 ⁇ M.
  • K D affinity constant
  • Modification of antibodies as described above may be prepared during synthesis of the antibody or by post-production modification, or when the antibody is in recombinant form using the known techniques of site-directed mutagenesis, random mutagenesis, or enzymatic cleavage and/or ligation of nucleic acids.
  • the antibody may be a derivative that contains modification compared to a parent antibody, i.e., by the covalent attachment of any type of molecule to the antibody such that covalent attachment does not prevent the antibody from binding to the target microbe.
  • Additional routine experimentation e.g., peptide mutation and binding analyses
  • peptide mutation and binding analyses can then be carried out to confirm whether the observed lack of binding of the test antibody is in fact due to binding to the same epitope as the reference antibody or if steric blocking (or another phenomenon) is responsible for the lack of observed binding.
  • steric blocking or another phenomenon
  • this sort can be performed using ELISA, RIA, surface plasmon resonance, flow cytometry or any other quantitative or qualitative antibody-binding assay available in the art.
  • Cross-competing antibodies can be identified using any suitable method in the art, for example by using competition ELISA or BIAcore assays where binding of the cross competing antibody to a particular epitope on the spike protein prevents the binding of an antibody of the invention or vice versa.
  • the antibody produces ⁇ 50%, ⁇ 60%, ⁇ 70%, ⁇ 80%, ⁇ 90% or 100% reduction of binding of the specific antibody disclosed herein.
  • Other techniques that may be used to determine antibody epitopes include hydrogen/deuterium exchange, X-ray crystallography and peptide display libraries (as described in the Examples). A combination of these techniques may be used to determine the epitope of the test antibody.
  • combinations comprising two or more antibodies of the invention, e.g. to maximise therapeutic effects and/or increase diagnostic power.
  • the invention provides a combination of antibodies comprising two or more of mAb184a-D10, mAb97A-D6 and mAb135a-D6.
  • a combination of the antibodies of the invention may be useful as a therapeutic cocktail.
  • the invention also provides a pharmaceutical composition comprising a combination of the antibodies of the invention, as explained further below.
  • a combination of the antibodies of the invention may be useful for diagnosis.
  • the invention also provides a diagnostic kit comprising a combination of the antibodies of the invention.
  • methods of diagnosing a disease or complication associated with bacteria infections in a subject as explained further below.
  • the antimicrobial agent provided herein comprises an antimicrobial moiety conjugated to linker that is selectively cleavable by said microbe.
  • the microbe expresses one or more proteins capable of cleaving said linker and said linker is cleaved by said one or more proteins.
  • the one or more proteins may be expressed on the surface of said microbe. More often the one or more proteins are extracellular proteins. The one or more proteins may be released or secreted by the microbe into the extracellular space.
  • the one or more proteins typically comprise one or more proteases.
  • the proteases are typically employed by the microbe to evade the host defence system.
  • the invention exploits these proteases by incorporating in the antimicrobial agent as described herein a peptide sequence, referred to as a linker herein, having a cleavage site recognised by such proteases.
  • the microbe typically expresses a protease and said linker comprises a protease recognition sequence specific for said protease.
  • the protease is typically secreted into the vicinity of the microbe.
  • the protease is typically a serine protease.
  • the protease may target a recognition site on a human protein.
  • the protease may target a recognition site on a human protein such as human IgA1 (hlgA1).
  • the protease may for example target a hinge region of said protein.
  • the IgA protease may be a serine protease (e.g. EC 3.4.21), such as an IgA-specific serine protease (e.g. EC 3.4.21.72), a metallo protease (e.g. EC 3.4.24) e.g. an IgA-specific metallo protease (e.g.
  • the IgA protease may be a serine endopeptidase (e.g. EC 3.4.21.72), which cleaves human immunoglobulin A molecules at specific proline-serine peptide bonds in the hinge region.
  • This enzyme is secreted by Gram-negative bacteria Neisseria gonorrhoeae, Neisseria meningitidis, and Haemophilus influenza.
  • a linker comprising this cleavage recognition site may be useful in an antimicrobial agent for targeting Neisseria gonorrhoeae, Neisseria meningitidis, or Haemophilus influenzae.
  • an antimicrobial agent of the invention may comprise: (a) a microbe-targeting moiety specific for Streptococcus species; (b) a linker comprising a cleavage recognition site for IgA metalloendopeptidase (e.g.
  • the IgA protease may target a recognition sequence as described herein.
  • the recognition sequence targeted by the protease is an amino acid sequence comprised in a human protein such as human IgA1.
  • the recognition sequence targeted by the protease is an amino acid sequence comprised in a hinge region of a human protein such as human IgA1.
  • the recognition sequence targeted by the protease is a group of formula [PRS] as described in more detail herein.
  • the protease may be at least 70% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34. In some embodiments the protease is at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34. Often the protease is at least 70% identical to the amino acid sequence of SEQ ID NO: 31 or 32, preferably 31.
  • the protease is at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% identical to the amino acid sequence of SEQ ID NO: 31 or 32, preferably 31.
  • SEQ ID NO A is the amino acid sequence of the IgA serine protease expressed by N. gonorrhoeae strain FA1090. All N. gonorrhoeae isolates secrete a highly specific IgA serine protease (IgAP) which cleaves the heavy ( ⁇ )-chain, in the 18-amino-acid hinge region of human IgA1 (hIgA1) as a means to subvert the host immune system.
  • IgAP highly specific IgA serine protease
  • IgA1 human IgA1
  • gonococcal IgAP Cleavage of human IgA1 (hIgA1) by the gonococcal IgAP generates Fab ⁇ and Fc ⁇ fragments resulting in the loss of Fc ⁇ -mediated effector functions, e.g. inhibition of adherence, despite the binding activity of the Fab ⁇ fragments. Consequently, binding of the Fab ⁇ fragments may block binding of immune activating immunoglobulins therefore inhibiting complement activation and bacterial clearance.
  • the IgA protease may target a recognition sequence which is a group of formula [PRS1] as described herein. In another embodiment the protease may be is at least 70% identical to the amino acid sequence of SEQ ID NO: 35.
  • the antimicrobial activity of the antibiotic compound may be activity in killing the bacterium.
  • the antimicrobial activity of the antibiotic compound may be activity in preventing replication or division of the bacterium.
  • the antimicrobial activity of the antibiotic compound may be activity in preventing movement of the bacterium.
  • the antibiotic compound may disrupt the bacterial cell wall or cell membrane.
  • the antibiotic compound may block influx or efflux of compounds from the bacteria.
  • the antibiotic compound may bind to a lipid on the bacterial cell membrane.
  • the antibiotic compound may disrupt a chemical gradient across the bacterial cell membrane.
  • the antibiotic compound may disrupt the proton motive force across the bacterial cell membrane.
  • antibiotic compounds which kill bacteria by disrupting the proton motive force across the bacterial cell membrane are believed to include antimicrobial peptides such as N-acylated tridecapeptides and or N-acylated tridecalipopeptides such as tridecaptic A1, described herein.
  • the antimicrobial moiety of the antimicrobial agent may be an antibiotic compound.
  • the antimicrobial moiety may be an antibiotic compound selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides.
  • guavanin 2 a polymixin, an octapeptin, a surfactin, a lichenysin, brevicidine, lacterocidine or daptomycin.
  • the antimicrobial agent is an antimicrobial peptide
  • the antimicrobial peptide is a tridecaptin or an analog thereof.
  • Tridecaptins are a group of linear cationic lipopeptides analogous to the polymyxins (Parachin, N. S. & Franco, O. L. New edge of antibiotic development: antimicrobial peptides and corresponding resistance. Front Microbiol 5, 147 (2014)).
  • tridecapeptides are produced by non-ribosomal peptide synthesis in Paenibacillus spp. and typically contain a mixture of both D and L amino acids as well as Diamino-butyric acid (Dab).
  • the antimicrobial agent is an antimicrobial peptide
  • the antimicrobial peptide is a N-acylated tridecapeptide or N-acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C 4-12 alkyl, C 4-12 alkenyl, or C 4-12 alkynyl group which is unsubstituted or which is substituted with 1, 2 or 3 substituents selected from CO, -OR a , -N(R a ) 2 , halogen, and -CN and each R a which may be the same or different is selected from H and unsubstituted C 1-2 alkyl, preferably H.
  • the antimicrobial agent is a variant of tridecaptin A 1 (TriA 1 ) or octyl-tridecaptin A 1 (Oct-TriA 1 ) comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A 1 , said substitutions are at positions selected from positions 1, 2, 3, 4, 6, 7, 9, 10, 11 or 13 of SEQ ID NO: 36.
  • residues D- Dab8, D-allo-Ile12 and D-Trp5 are believed to be associated with improved antimicrobial activity.
  • the antimicrobial agent is a variant of tridecaptin A 1 (TriA 1 ) or octanoyl-tridecaptin A 1 (Oct-TriA 1 ) comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A 1
  • said variant comprises from 1 to 4, preferably from 1 to 3, e.g. 1 or 2, more preferably 1 substitution in the amino acid sequence of SEQ ID NO: 36.
  • the antimicrobial moiety is octyl-tridecaptin A 1 .
  • TriA1 peptides such as TriA1 and Oct-TriA1 have potent, selective antimicrobial activity against Gram-negative bacteria (Lohans, C. T. et al.
  • TriA1 cationic amino acids i.e. Dab of TriA1 interact with anionic bacterial lipopolysaccharide in the outer membrane.
  • TriA1 selectively binds the pentapeptide of Lipid II, the precursor of peptidoglycan biosynthesis, from Gram negative bacteria through interaction with the DAP residue whereby it exerts its bactericidal activity by disruption of proton motive force.
  • the linker links the microbe-targeting moiety to the antimicrobial moiety and can be cleaved by the target microbe which the microbe- targeting moiety targets.
  • the linker is or comprises a polymer.
  • the linker comprises a feature which allows it to be selectively cleaved by the microbe targeted by the microbe- targeting moiety.
  • the linker comprises or consists of a peptide (e.g. an oligopeptide). Any suitable length of linker can be used providing it comprises a suitable cleavage site for selective cleavage by the target microbe.
  • the linker comprises a peptide of from about 5 to about 50 amino acids in length.
  • the linker comprises a peptide comprising a protease recognition site is a group of formula [PRS], wherein said group of formula [PRS] is a group of formula [PRS1] or [PRS2]: Yaa – Pro – Xaa – Pro [PRS1] Gly – Gly – Ala [PRS2] wherein: Yaa is selected from Arg-Pro; Thr-Pro; Ala-Pro; Gly-Pro; and Pro; and Xaa is selected from Thr; Ser and Ala.
  • Linkers comprising a protease recognition site of formula PRS1 are particularly useful when the target microbe expresses a protease having an amino acid sequence at least 70% identical to any one of SEQ ID NOs: 31 to 34.
  • Suitable proteases include the IgA specific serine protease proteases expressed by bacteria of family Neisseriaceae, Streptococcaceae, and Pasteurellaceae.
  • Preferable proteases include the IgA proteases expressed by Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, and Haemophilus influenzae.
  • the protease is expressed by Neisseriaceae gonorrhoeae or Neisseria meningitides, preferably Neisseriaceae gonorrhoeae. Without being bound by theory, these proteases are believed to cleave peptides having a consensus recognition sequence of PRS1.
  • Yaa is preferably selected from Ala-Pro and Pro. Most preferably Yaa is Pro.
  • Xaa is preferably selected from Ser and Ala. In one embodiment Xaa is Ser. In one embodiment Xaa is Ala.
  • each Aaa is independently selected from L- and D- isomers of natural amino acids. In some embodiments, each Aaa is independently selected from L- isomers of natural amino acids. In some embodiments, each Aaa is independently selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys. In some embodiments, each Baa is independently selected from L- and D- isomers of natural amino acids. In some embodiments, each Baa is independently selected from L- isomers of natural amino acids.
  • the group of formula (II) is a group of formula (II-A) D – X – (Aaa) n – Yaa – Pro – Xaa – Pro – (Baa) m – Y – Caa wherein each D, X, Aaa, Baa, n, m, Yaa, Xaa, Y and Caa are as defined herein.
  • the antimicrobial agent comprises a group of formula (III): D – X – Aaa1 – Aaa2 – Aaa3 – [PRS] – Baa1 – Baa2 – Baa3 – Y – Caa
  • - Aaa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys
  • - Aaa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys
  • - Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys
  • - Baa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, P
  • X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta- decanoic acid).
  • O2Oc 8-amino-3,6-dioxaoctanoic acid
  • beta-alanine PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta- decanoic acid.
  • X is absent or is O2Oc.
  • X is O2Oc.
  • Y is as defined for formula X.
  • Y is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta- decanoic acid).
  • Y is absent or is O2Oc.
  • Y is O2Oc.
  • Aaa1 is selected from Val, Leu, Ile, Ala, Pro, Arg and Lys.
  • Aaa1 is selected from Val, Leu, Pro, and Arg.
  • Baa1 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa1 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa1 is Gln or Val. In some embodiments, Baa2 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa2 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa2 is Ala or Phe.
  • Baa3 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa3 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa3 is Asn or Ser.
  • the group of formula (III) is a group of formula (III-A) D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 – Y – Caa wherein each D, X, Aaa1, Aaa2, Aaa3, Baa1, Baa2, Baa3, Yaa, Xaa, Y and Caa are as defined herein.
  • the group of formula (III-A) is a group of formula (III-A3) D – X – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – Y – Cys
  • the group of formula (III-A) is a group of formula (III-A4) D – O2Oc – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – O2Oc – Cys.
  • the C terminal amino acid is amidated.
  • the group of formula (III-A1) is D – X – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – Y – Cys-NH 2
  • the group of formula (III-A2) is D – O2Oc – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – O2Oc – Cys-NH 2 .
  • the group of formula (III-A3) is D – X – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – Y – Cys-NH 2
  • the group of formula (III-A4) is D–O2Oc–Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – O2Oc – Cys-NH 2 .
  • D is an antimicrobial peptide.
  • D may be any of the antimicrobial peptides disclosed herein.
  • D is an N-acylated tridecapeptide or N-acylated tridecalipopeptide (e.g. TriA1, TriB1, TriM1 and derivatives thereof).
  • D is Oct-TriA1
  • the antimicrobial agent thus comprises a polypeptide of formula PRN2028 or PRN2029: Conjugation
  • the microbe-targeting moiety is conjugated to the antimicrobial moiety by the cleavable linker as discussed above.
  • the cleavable linker typically comprises a terminal natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on said microbe-targeting moiety, for example a group Caa as described above.
  • the terminal group may for example be a cysteine or a lysine residue.
  • the attachment between the linker and the microbe-targeting moiety is not limited and any suitable attachment chemistry can be used. Many suitable reactive groups and their chemical targets are known in the art.
  • Some exemplary reactive groups and their corresponding targets include aryl azides which may react with amine, carbodiimides which may react with amines and carboxyl groups, hydrazides which may react with carbohydrates, hydroxmethyl phosphines which may react with amines, imidoesters which may react with amines, isocyanates which may react with hydroxyl groups, carbonyls which may react with hydrazines, maleimides which may react with sulfhydryl groups, NHS-esters which may react with amines, PFP-esters which may react with amines, psoralens which may react with thymine, pyridyl disulfides which may react with sulfhydryl groups, vinyl sulfones which may react with sulfhydryl amines and hydroxyl groups, vinylsulfonamides, and the like.
  • click chemistry for conjugating the polypeptide to the polynucleotide
  • click chemistry include click chemistry.
  • Many suitable click chemistry reagents are known in the art. Suitable examples of click chemistry include, but are not limited to, the following: (a) copper(I)-catalyzed azide-alkyne cycloadditions (azide alkyne Huisgen cycloadditions); (b) strain-promoted azide-alkyne cycloadditions; including alkene and azide [3+2] cycloadditions; alkene and tetrazine inverse-demand Diels-Alder reactions; and alkene and tetrazole photoclick reactions; (c) copper-free variant of the 1,3 dipolar cycloaddition reaction, where an azide reacts with an alkyne under strain, for example in a cyclooctane ring such as in bicycle[6.1.0]non
  • the antimicrobial moiety can be conjugated to the microbe-targeting moiety via a linker (e.g. a peptide linker) wherein the C-terminus of the linker is attached to the antimicrobial moiety and the N terminus of the linker is attached to the microbe-targeting moiety. More often, the N-terminus of the linker is attached to the antimicrobial moiety and the C terminus of the linker is attached to the microbe-targeting moiety.
  • the linker may comprise a naturally occurring reactive functional group which can be used to facilitate conjugation to the microbe-targeting moiety. For example, a cysteine residue can be used to form a disulphide bond to a cysteine residue on the microbe- targeting moiety.
  • a cysteine residue can be used to react with a mameimide group.
  • a microbe-targeting moiety such as an antibody as described herein can conjugated to a linker-antimicrobial moiety construct having a C- terminal cysteine residue using MBS (m-maleimidobenzoyl-N-hydroxysuccinimide ester).
  • MBS is an amine-to-sulfhydryl crosslinker and thus can attach the cysteine residue of the construct to a lysine residue of the microbe-targeting moiety.
  • Other cysteine/lysine reactive groups can be used.
  • the antimicrobial agent provided herein thus comprises a microbe-targeting moiety conjugated to a construct comprising a linker selectively cleavable by said microbe; and an antimicrobial moiety.
  • the antimicrobial agent comprises at least 1, at least 2, at least 3, at least 5, at least 6, at least 7, or at least 8 such constructs.
  • the antimicrobial agent comprises between 1 and 20 of such constructs, for example between 5 and 10 of such constructs.
  • antimicrobial agents which comprise higher numbers of constructs may have higher antimicrobial activity than antimicrobial agents which comprise lower numbers of constructs.
  • Antimicrobial agents which comprise lower numbers of constructs may be easier to generate and/or allow the use of smaller microbe- targeting moieties.
  • the invention provides: an antimicrobial agent comprising a) a microbe-targeting moiety b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is an antibody; wherein the linker and antimicrobial moiety are comprised in a moiety of form D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 Y — Caa wherein D is the antimicrobial moiety; X is absent or is O2Oc; Aaa1 is Val or Leu; Aaa2 is Val or Pro; Aaa3 is absent or is Arg; Yaa is Ala-Pro or Pro; Xaa is Ser or Ala; Baa1 is Gln or Val; Baa2 is Ala or Phe; Baa3 is
  • the linker and microbial moiety are of the form: D – O2Oc – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – O2Oc – Cys-NH 2 Yaa is Ala-Pro and Xaa is Ser; and/or D is Oct-Tri-A1; and/or Cys is crosslinked to a Lys residue of said microbe-targeting moiety.
  • the linker and microbial moiety are of the form: D–O2Oc – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – O2Oc – Cys-NH 2 Yaa is Pro; Xaa is Ala; and/or D is Oct-Tri-A1; and/or Cys is crosslinked to a Lys residue of said microbe-targeting moiety.
  • Polynucleotides, vectors and host cells The invention also provides one or more isolated polynucleotides (e.g. DNA) encoding an antibody described herein.
  • a polynucleotide described herein may be provided in the form of an expression cassette, which includes control sequences operably linked to the inserted sequence, thus allowing for expression of the antibody of the invention in vivo.
  • the invention also provides one or more expression cassettes encoding the one or more polynucleotides that encoding an antibody described herein. These expression cassettes, in turn, are typically provided within vectors (e.g.
  • the invention provides a vector encoding an antibody described herein.
  • the invention provides vectors which collectively encode an antibody described herein.
  • the vectors may be cloning vectors or expression vectors.
  • a suitable vector may be any vector which is capable of carrying a sufficient amount of genetic information, and allowing expression of a polypeptide described herein.
  • the polynucleotides, expression cassettes or vectors described herein are introduced into a host cell, e.g. by transfection.
  • the invention also provides a host cell comprising the one or more polynucleotides, expression cassettes or vectors of the invention.
  • cephalosporins examples include Cefazolin, Ceftriaxone, Ceftazidine and Ceftobiprole.
  • penems examples include Faropenem.
  • the other antibiotic agent may be selected from tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides.
  • tetracyclines include demeclocycline, doxycycline, eravacycline, minocycline, omadacycline, sarecycline and tetracycline.
  • Examples of quinolones include ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin and gemifloxacin.
  • Examples of lincomycins include clindamycin and lincomycin.
  • Examples of macrolides include azithromycin, clarithromycin, erythromycin, and fidaxomicin.
  • Examples of sulphonamides include sulfamethoxazole, trimethoprim and sulfasalazine.
  • Examples of glycopeptides include dalbavancin, oritavancin, telavancin and vancomycin.
  • Examples of aminoglycosides include gentamicin, tobramycin and amikacin.
  • the agents provided herein may find particular use in treating or preventing bacterial infection caused by bacteria which are resistant to treatment with antibiotic agents when administered alone.
  • the agents provided herein may be useful in treating or preventing bacterial infection caused by drug (e.g. antibiotic) resistant bacteria, particularly where the resistance is caused by the expression (e.g. upregulated expression) of multi-drug efflux pumps.
  • the resistance may be caused by expression (e.g. upregulated expression) of tripartite multidrug efflux pumps of family HAE-RND (hydrophobic and ampiphilic efflux resustance-nodulation cell division family).
  • HAE-RND hydrophobic and ampiphilic efflux resustance-nodulation cell division family.
  • MtrE multi- drug resistance pumps
  • the agents and compositions provided herein the invention are useful in treating or preventing bacterial infection.
  • the invention therefore also provides a method of treating or preventing bacterial infection in a subject, which method comprises administering to said subject an effective amount of an agent or composition as described herein.
  • an agent or composition as described herein for the manufacture of a medicament for use in treating or preventing bacterial infection.
  • the agents of the invention are useful in combination with a further antibacterial compound.
  • the invention therefore provides an agent of the invention for use in treating or preventing bacterial infection, wherein such use comprises co-administering the agent of the invention with a further antibacterial compound.
  • Preferred non-human animals include, but are not limited to, primates, such as marmosets or monkeys, commercially farmed animals, such as horses, cows, sheep or pigs, and pets, such as dogs, cats, mice, rats, guinea pigs, ferrets, gerbils or hamsters.
  • the subject can be any animal that is capable of being infected by a bacterium as described in more detail herein.
  • the agents and compositions described herein are useful in the treatment of bacterial infection which occurs after a relapse following an antibiotic treatment.
  • the compounds, compositions and combinations can therefore be used in the treatment of a patient who has previously received antibiotic treatment for the (same episode of) bacterial infection.
  • the bacterium may be resistant to one or more antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and/or aminoglycosides. Exemplary compounds in these classes are described in more detail herein.
  • the bacterial infection may be caused by bacteria from the families Neisseriaceae, Streptococcaceae, Pasteurellaceae and/or Pseudomonadaceae. The bacterial infection is often caused by bacteria from the families Neisseriaceae, Streptococcaceae, and/or Pasteurellaceae.
  • the bacterial infection is caused by bacteria from the family Neisseriaceae.
  • the bacterial infection may be caused Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, Haemophilus influenza or Pseudomonas aeruginosa. More typically the bacterial infection is caused by Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, or Haemophilus influenza. Still more typically the bacterial infection is caused by Neisseriaceae gonorrhoeae or Neisseria meningitides, preferably Neisseriaceae gonorrhoeae.
  • the bacterial infection may be caused by Neisseriaceae gonorrhoeae strain FA1090.
  • the agent or composition of the invention may be used to treat or prevent infections and conditions caused by any one or a combination of the above-mentioned bacteria.
  • the agent or composition of the invention may be used in the treatment or prevention of any suitable pathological condition caused by a microbial infection, upper and / or lower respiratory tract infections, skin and soft tissue infections and / or urinary tract infections.
  • the agent or composition of the invention may be used in the treatment or prevention of gonorrhoea, disseminated gonococcemia, septic arthritis, gonococcal ophthalmia neonatorum, pelvic inflammatory disease, ectopic pregnancy, pelvic scarring (including infertility arising from pelvic scarring), pharyngitis, proctitis, and HIV.
  • Such conditions may be particularly amenable to treatment when the microbial infection is caused by Neisseriaceae gonorrhoeae.
  • the agent or composition of the invention may be used in the treatment or prevention of meningitis, meningococcemia and septicaemia.
  • Such conditions may be particularly amenable to treatment when the microbial infection is caused by Neisseria meningitides.
  • the agent or composition of the invention may be used in the treatment or prevention of pneumonia, meningitis, sepsis, otitis media, pericarditis, epiglottitis, septic arthritis, cellulitis, and osteromyelitis.
  • Such conditions may be particularly amenable to treatment when the microbial infection is caused by Haemophilus influenza.
  • the agent or composition of the invention may be used in the treatment or prevention of pneumonia and sepsis.
  • Such conditions may be particularly amenable to treatment when the microbial infection is caused by Streptococcus pneumoniae.
  • the agent or composition of the invention may be used in the treatment or prevention of pneumonia (e.g.
  • An agent or composition of the invention can be administered to a subject in need thereof in order to prevent the onset or reoccurrence of one or more symptoms of the bacterial infection. This is prophylaxis.
  • the subject can be asymptomatic.
  • the subject is typically one that has been exposed to the bacterium.
  • a prophylactically effective amount of the agent or formulation is administered to such a subject.
  • a prophylactically effective amount is an amount which prevents the onset of one or more symptoms of the bacterial infection.
  • An agent or composition provided herein can be administered to the subject in order to treat one or more symptoms of the bacterial infection.
  • the subject is typically symptomatic.
  • a therapeutically effective amount of the agent or composition is administered to such a subject.
  • a therapeutically effective amount is an amount effective to ameliorate one or more symptoms of the disorder.
  • the agent or composition provided herein may be administered in a variety of dosage forms. Thus, it can be administered orally, for example as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules.
  • compositions may also be administered parenterally, whether subcutaneously, intravenously, intramuscularly, intrasternally, transdermally or by infusion techniques.
  • the agent or composition may also be administered as a suppository.
  • the agent or composition may be administered via inhaled (aerosolised) or intravenous administration, most preferably by inhaled (aerosolised) administration.
  • Therapeutic compositions typically must be sterile and stable under the conditions of manufacture and storage.
  • the composition can be formulated as a solution, microemulsion, liposome, or other ordered structure suitable to high drug concentration.
  • the agent or composition is typically formulated for administration with a pharmaceutically acceptable carrier or diluent. Examples of suitable aqueous carriers include water, buffered water and saline.
  • suitable pharmaceutically acceptable carriers include ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate.
  • isotonic agents for example, sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride in the composition.
  • solid oral forms may contain, together with the active compound(s), diluents, e.g. lactose, dextrose, saccharose, cellulose, corn starch or potato starch; lubricants, e.g.
  • binding agents e.g. starches, arabic gums, gelatin, methylcellulose, carboxymethylcellulose or polyvinyl pyrrolidone
  • disaggregating agents e.g. starch, alginic acid, alginates or sodium starch glycolate
  • dyestuffs effervescing mixtures
  • sweeteners effervesc
  • Such pharmaceutical preparations may be manufactured in known manner, for example, by means of mixing, granulating, tableting, sugar coating, or film coating processes.
  • the agent or composition may be formulated for inhaled (aerosolised) administration as a solution or suspension.
  • the agent or composition may be administered by a metered dose inhaler (MDI) or a nebulizer such as an electronic or jet nebulizer.
  • MDI metered dose inhaler
  • a nebulizer such as an electronic or jet nebulizer.
  • the agent or composition may be formulated for inhaled administration as a powdered drug, such formulations may be administered from a dry powder inhaler (DPI).
  • DPI dry powder inhaler
  • the agent or composition When formulated for inhaled administration, the agent or composition may be delivered in the form of particles which have a mass median aerodynamic diameter (MMAD) of from 1 to 100 ⁇ m, preferably from 1 to 50 ⁇ m, more preferably from 1 to 20 ⁇ m such as from 3 to 10 ⁇ m, e.g. from 4 to 6 ⁇ m.
  • MMAD mass median aerodynamic diameter
  • the agent or composition is delivered as a nebulized aerosol, the reference to particle diameters defines the MMAD of the droplets of the aerosol.
  • the MMAD can be measured by any suitable technique such as laser diffraction.
  • Liquid dispersions for oral administration may be syrups, emulsions and suspensions.
  • the syrups may contain as carriers, for example, saccharose or saccharose with glycerine and/or mannitol and/or sorbitol.
  • Suspensions and emulsions may contain as carrier, for example a natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol.
  • the suspension or solutions for intramuscular injections or inhalation may contain, together with the active compound, a pharmaceutically acceptable carrier, e.g. sterile water, olive oil, ethyl oleate, glycols, e.g. propylene glycol, and if desired, a suitable amount of lidocaine hydrochloride.
  • Solutions for inhalation, injection or infusion may contain as carrier, for example, sterile water or preferably they may be in the form of sterile, aqueous, isotonic saline solutions.
  • Pharmaceutical compositions suitable for delivery by needleless injection, for example, transdermally, may also be used.
  • a therapeutically or prophylactically effective amount of the agent or composition may be administered to a subject.
  • the dose may be determined according to various parameters, especially according to the compound used; the age, weight and condition of the subject to be treated; the route of administration; and the required regimen. Again, a physician will be able to determine the required route of administration and dosage for any particular subject.
  • a typical daily dose is from about 0.01 to 100 mg per kg, preferably from about 0.1 mg/kg to 50 mg/kg, e.g. from about 1 to 10 mg/kg of body weight, according to the activity of the specific inhibitor, the age, weight and conditions of the subject to be treated, the type and severity of the disease and the frequency and route of administration. Preferably, daily dosage levels are from 5 mg to 2 g.
  • the agent or composition is administered to a subject in combination with another active agent (for example together with a further antibiotic agent), the dose of the other active agent can be determined as described above. The dose may be determined according to various parameters, especially according to the agent used; the age, weight and condition of the subject to be treated; the route of administration; and the required regimen.
  • a typical daily dose is from about 0.01 to 100 mg per kg, preferably from about 0.1 mg/kg to 50 mg/kg, e.g. from about 1 to 10 mg/kg of body weight, according to the activity of the specific inhibitor, the age, weight and conditions of the subject to be treated, the type and severity of the disease and the frequency and route of administration. Preferably, daily dosage levels are from 5 mg to 2 g.
  • the antibacterial properties of the compounds described herein mean that they are also useful in the treatment of bacterial infection in vitro, i.e. other than by the treatment of human or animal subjects.
  • the invention also provides a cleaning composition comprising an agent as described herein.
  • the cleaning composition may further comprise, for example, a detergent, a surfactant (including ionic and non-ionic surfactants), a diluent, a bleach (including a hypochlorite such as sodium hypochlorite or calcium hypochlorite, chlorine, chlorine dioxide, hydrogen peroxide or an adduct thereof, sodium perborate, and sodium percarbonate), an alcohol (such as ethanol or isopropanol), or a disinfectant.
  • a detergent including ionic and non-ionic surfactants
  • a diluent including a hypochlorite such as sodium hypochlorite or calcium hypochlorite, chlorine, chlorine dioxide, hydrogen peroxide or an adduct thereof, sodium perborate, and sodium percarbonate
  • a bleach including a hypochlorite such as sodium hypochlorite or calcium hypochlorite, chlorine, chlorine dioxide, hydrogen peroxide or an adduct thereof, sodium perborate, and sodium percarbonate
  • the disinfectant may be selected from benzyl-4-chlorophenol, amylphenol, phenylphenol, glutaraldehyde, alkyl dimethyl benzyl ammonium chloride, alkyl dimethyl ethylbenzyl ammonium chloride, iodine, peracetic acid and chlorine dioxide.
  • the detergent may be an alkaline detergent such as sodium hydroxide, sodium metasilicate, or sodium carbonate, or an acid detergent such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, citric acid, or tartaric acid.
  • kits comprising antibodies or other compositions of the invention and instructions for use.
  • the kit may further contain one or more additional reagents, such as an additional therapeutic or prophylactic agent as discussed herein.
  • the kit may comprise an antimicrobial agent as described herein together with instructions for use.
  • Also provided herein is a method of making an antimicrobial agent as described herein, comprising conjugating an antimicrobial moiety to a microbe-targeting moiety via a linker, wherein said linker is selectively cleavable by said microbe.
  • the antimicrobial moiety, microbe-targeting moiety and linker are as described herein.
  • protease-cleavable oligopeptide comprising a group of formula (Aaa) n – [PRS] – (Baa) m – Y – Caa wherein - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on a microbe-targeting moiety such as an antibody; and - [PRS], (Aaa), (Baa), n, m and Y are as defined in herein in more detail.
  • a protease-cleavable oligopeptide as described herein to conjugate a microbe-targeting moiety to an antimicrobial moiety.
  • microbe-targeting moiety and said antimicrobial moiety are as defined herein. It is a benefit of the present invention that the protease-cleavable oligopeptides described herein are capable of being cleaved even when conjugated to a microbe-targeting moiety and/or a antimicrobial moiety as described herein.
  • the invention also relates to identifying subjects that have a bacterial infection, such as infection by N.gonorrhoeae.
  • the methods and uses of the invention may involve identifying the presence of a bacteria (e.g. N.gonorrhoeae) in a sample. The detection may be carried out in vitro or in vivo.
  • the invention relates to population screening.
  • said methods and uses comprise contacting the sample with an agent as described herein and determining the extent of bacterial cell killing by the agent, wherein the extent of selective cell killing can be correlated with the concentration of the bacteria (e.g. N.gonorrhoeae) in the sample.
  • the invention relates to analysing samples from subjects.
  • the sample may be tissues, cells and biological fluids isolated from a subject, as well as tissues, cells and fluids present within a subject.
  • the sample may be blood and a fraction or component of blood including blood serum, blood plasma, or lymph. Typically, the sample is from a throat swab, nasal swab, or saliva.
  • the sample to be analysed is contacted with an agents as described herein.
  • the sequences are aligned for optimal comparison purposes (e.g. gaps can be introduced in a first sequence for optimal alignment with a second sequence).
  • the nucleotide or amino acid residues at each position are then compared.
  • a position in the first sequence is occupied by the same nucleotide or amino acid as the corresponding position in the second sequence, then the nucleotides or amino acids are identical at that position.
  • sequence comparison is carried out over the length of the reference sequence. For example, if the user wished to determine whether a given (“test”) sequence is 95% identical to SEQ ID NO: 3, SEQ ID NO: 3 would be the reference sequence. To assess whether a sequence is at least 95% identical to SEQ ID NO: 3 (an example of a reference sequence), the skilled person would carry out an alignment over the length of SEQ ID NO: 3, and identify how many positions in the test sequence were identical to those of SEQ ID NO: 3. If at least 95% of the positions are identical, the test sequence is at least 95% identical to SEQ ID NO: 3. If the sequence is shorter than SEQ ID NO: 3, the gaps or missing positions should be considered to be non-identical positions.
  • a C 4-12 alkyl group is a linear or branched alkyl group containing from 4 to 12 carbon atoms.
  • a C 4-12 alkyl group is often a C 6-10 alkyl group such as a C 8-10 alkyl group.
  • a C 1-2 alkyl group may be for example methyl or ethyl, typically methyl.
  • the alkyl groups may be the same or different.
  • a C 4-12 alkenyl group is a linear or branched group containing from 4 to 12 carbon atoms and having one or more, e.g. one or two, typically one double bonds.
  • a C 4-12 alkenyl group is often a C 6-10 alkenyl group such as a C 8-10 alkenyl group. For the avoidance of doubt, where two alkenyl groups are present, the alkenyl groups may be the same or different.
  • a C 4-12 alkynyl group is a linear or branched group containing from 4 to 12 carbon atoms and having one or more, e.g. one or two, typically one triple bonds.
  • a C 4-12 alkynyl group is often a C 6-10 alkynyl group such as a C 8-10 alkynyl group. For the avoidance of doubt, where two alkynyl groups are present, the alkynyl groups may be the same or different.
  • the agent described herein comprises a peptide (e.g. a peptide-based linker and/or a peptide-based antimicrobial moiety
  • the peptide can be synthesized by standard methods such as solid-phase peptide synthesis, known to those of skill in the art and commercially available from providers such as ISCA Biochemicals (Exeter, UK).
  • Agents described herein are typically used in enantiomerically or diastereoisomerically pure form, or in the form of a mixture of isomers. Further, for the avoidance of doubt, the agents of the invention may be used in any tautomeric form.
  • Detection of MtrE by the mAbs of a range of clinical isolates was also examined by Western blot analysis ( Figure 1B).
  • the mAbs identified a band of the predicted molecular mass of MtrE expressed by over 50 gonococcal clinical isolates.
  • Peptides were synthesised to conjugate to the mAbs, resulting in antibody-peptide conjugates (APCs): mAb 184a-D10:PRN2028, mAb 184a-D10:PRN2029 and mAb 184a- D10:PRN2208.
  • the peptide sequences are show in Table 1, and the strategy and structure of the APCs are shown in Figures 2A and 2B.
  • Each of PRN2028 and PRN2029 comprises the sequence of the antimicrobial peptide, Oct-TriA1, together with a linker sequence which is predicted to be cleaved by the gonococcal IgA proteases, and a terminal cysteine for conjugation.
  • Figures 6A and 6B show the IgAP cleavage sites in PRN2028 and PRN029, which would result in the release of antimicrobial peptides corresponding to PRN 1967 and PRN 1968, respectively.
  • PRN 2208 comprises the sequence of the antimicrobial peptide, Oct-TriA1, together with a linker sequence which is not cleaved by the gonococcal IgA proteases, and a terminal cysteine for conjugation.
  • ⁇ mtrE and ⁇ igAP strains Genomic DNA from two gonococcal strains, MS11 and FA1090, was isolated.
  • MtrE NEIS1632
  • NEBuilder® assembly tool was used to design primers using pUC19 plasmid as a template per the manufacturer’s instructions. Overlap 1632 primers were designed for insertional inactivation of MtrE with a Kan cassette. Fragments were ligated into pUC19 plasmid digested with BamHI and XbaI. Assembled products were transformed into E.
  • gonorrhoeae as previously described (Dillard, J. P. Genetic Manipulation of Neisseria gonorrhoeae. Curr Protoc Microbiol Chapter 4, Unit4A.2.16 (2011). Production of recombinant MtrE Genomic DNA was isolated. mtrE was amplified from N. gonorrhoeae FA1090 genomic DNA using primers Fwd 1632 (5′- AGCCTTTGCATTGCATATGTGCACCATGATT-3′; SEQ ID NO: 37; Nde I site underlined) and Rev 1632 (5′- TTGTTTGCCCGGATCCTTATTTGCCGGTTT-3′; SEQ ID NO: 38; BamHI site underlined).
  • MtrE expression E. coli B834 containing pET14b:mtrE was grown in TB medium and IPTG was added to a final concentration of 1 mM. Bacteria were subsequently grown for 24 h at 22°C and harvested. The lysates were centrifuged, and recombinant MtrE was purified by affinity chromatography using a HisTrap column and eluted with 300 mM imidazole. Further purification was performed by size exclusion chromatography. Protein concentrations were estimated.
  • MtrE mAbs Female BALB/c mice (6 to 8 weeks old; Charles River, Margate, UK) were immunized with recombinant MtrE (20 ⁇ g) adsorbed to aluminum hydroxide [final composition, 0.5 mg/ml Al(OH) 3 , 10 mM histidine-HCl] by mixing overnight at 4°C on an end to end rocker. Antigens were given by the intraperitoneal route on days 0, 21, and 35. The spleen and sera were harvested on day 49 under terminal anesthesia by cardiac puncture. B lymphocytes were fused to NS0 myeloma cells (Galfrè, G. & Milstein, C. Preparation of monoclonal antibodies: strategies and procedures.
  • Hybridoma clone supernatants were screened by ELISA against recombinant MtrE prior to positive hybridomas being cloned by limiting dilution and reselected by ELISA (Caesar, J. J. et al. Competition between antagonistic complement factors for a single protein on N. meningitidis rules disease susceptibility. Elife 3 (2014)).
  • Antibodies were sequenced by whole transcriptome shotgun sequencing (RNA- Seq).
  • Hybridomas were cultured in IMDM medium containing 10% FBS and incubated at 37oC in a 5% CO2 environment. Total RNA was extracted from cells and a barcoded cDNA library generated through RT-PCR using a random hexamer.
  • Next Generation Sequencing was performed on an Illumina HiSeq sequencer. Contigs were assembled and data is mined for antibody sequences using a pattern match approach which identifies all viable antibody sequences (i.e. those not containing stop codons). The species and isotype of the identified antibody genes were confirmed and variable heavy and variable light domains were identified separately. Sequences were compared with known aberrant (i.e. non-functional) antibody genes that are present in many hybridomas and these genes were removed from analysis when necessary. mAb screening ELISA ELISA plates were coated with recombinant MtrE (5 ⁇ g/ml, 50 ⁇ l per well) for three hours at room temperature before blocking overnight with 3% skimmed milk in PBS 0.05% Tween 20.
  • mAb purification and isotyping Murine anti-MtrE mAbs were purified from tissue culture supernatants by protein G affinity chromatography. Briefly, hybridoma tissue culture supernatant was diluted 50:50 with mAb binding buffer (50mM sodium acetate, pH 5.0). Protein G chromatography cartridges (Pierce, ThermoFisher Scientific) were equilibrated with 20 ml of binding buffer prior to applying diluted supernatant manually at a flow rate of 1 ml/ min.
  • gonorrhoeae isolates bacteria were grown on GCB agar overnight and 1 ⁇ 10 9 CFU/ml bacteria were suspended in SDS-PAGE loading buffer (100 mM Tris-HCl, pH 6.8, 20 ⁇ M ⁇ -mercaptoethanol, 4% SDS, 0.2% bromophenol blue, 20% glycerol) prior to separation of on 14% polyacrylamide gels. Proteins were transferred to Immobilon P polyvinylidene difluoride (PVDF) membrane (Millipore, USA) using the Trans-Blot SD semi-dry transfer system (Bio-Rad, USA).
  • PVDF Immobilon P polyvinylidene difluoride
  • Membranes were blocked in 3% (wt/vol) skimmed milk-PBS with 0.05% (vol/vol) Tween 20 overnight and then incubated with neat hybridoma tissue culture supernatant or purified anti-MtrE mAb (5 ⁇ g/ ml) in antibody dilutant (1% (w/v) skimmed milk in PBS). Membranes were washed three times in PBS with 0.05% (vol/vol) Tween 20, and incubated with goat anti-mouse HRP (Dako, UK), and subjected to further washing. Binding was detected using ECL Western blotting detection kit (Amersham, USA). Flow cytometry N.
  • gonorrhoeae was grown on GCB agar overnight and quantified as described above.
  • 1 ⁇ 10 8 CFU/ml of bacteria were re-suspended in 100 ⁇ l of mAb (5 ⁇ g/ ml) for 30 min at room temperature.
  • wash buffer 0.05% (w/v) BSA/PBS
  • binding was detected following incubation for 30 min with goat anti-mouse IgG-Alexa fluor ® 647 conjugate (Molecular Probes, Life Technologies) at room temperature. Samples were washed three times in wash buffer and then fixed in 3% paraformaldehyde for 30 minutes at room temperature.
  • MBS (final concentration, 5 mM) was added to the purified mAb (0.1 mM in BupH TM PBS) and incubated at room temperature for 60 minutes. Excess MBS was removed over ZebaTM Spin desalting columns (ThermoFisher scientific) according to manufactures instructions. Briefly, columns were centrifuged at 1500 ⁇ g for 1 minute to remove storage solution prior to washing the column with three times with BupH TM PBS . Sample was applied the centre of the compacted resin bed and eluted by centrifugation 1500 ⁇ g for 2 minutes. Finally the peptide (1.25 mM) was added in 100- fold molar excess and incubated for at least 2 hours at room temperature.
  • mAb:peptide conjugates were dialysed using slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) into PBS (Oxoid) overnight at 4 o C.
  • MALDI-TOF MS analysis of mAb:peptide conjugates Matrix-Assisted Laser Desorption Ionization time of flight mass spectrometry (MALDI-TOF-MS) was conducted using a Bruker Microflex LRF MALDI TOF mass spectrometer, equipped with a 60Hz nitrogen laser at 337nm.
  • Super DHB mixture of 2,5- dihydroxybenzoic acid (2,5-DHB) and 2-hydroxy-5-methoxybenzoic acid
  • 2,5-DHB 2,5- dihydroxybenzoic acid
  • 2-hydroxy-5-methoxybenzoic acid was used as a matrix.
  • Cleavage of hIgA1 by gonococcal IgAP N. gonorrhoeae strains were assessed for IgA1 protease activity by incubation with purified hIgA1 (abcam, UK).
  • hIgA1 (5 ⁇ g) or PBS as a control, was incubated with the supernatant (20 ⁇ l) from a 24 h culture of N. gonorrhoeae grown GW for 4 h at 37 °C.
  • Cleavage was assessed by SDS-PAGE stained with Coomassie blue or after transfer to PDVF and probed with anti-hIgA-HRP. Cleavage and detection of Oct-TriA 1 derivatives and mAb:peptide conjugates
  • supernatant from N. gonorrhoeae strains were harvested after growth for 24 h in FB medium. Supernatant was then dialysed overnight into PBS using a slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) to remove low molecular weight proteins and retain IgAP.
  • Peptides (350 ⁇ g) or mAb:peptide conjugates were incubated for 4 h at 37 °C into dialysed supernatant (100 ⁇ l). Samples were subsequently desalted using PierceTM Peptide Desalting Spin Columns (Thermo Scientific) according to manufactures instructions. Briefly, centrifuge desalting columns at 5,000 ⁇ g for 1 minute to remove packing solution. Wash the spin column twice with acetonitrile, and twice with 0.1% trifluoroacetic acid. Load sample and centrifuge at 3,000 ⁇ g for 1 minute prior to washing with 0.1% trifluoroacetic acid. Samples were eluted twice with 300 ⁇ l 50% acetonitrile, 0.1% trifluoroacetic acid.
  • Bacterial suspensions in PBS were adjusted to OD A600 nm of 1.0 (equivalent to approximately 1 ⁇ 10 9 CFU/ml bacteria). The bacteria were subsequently diluted to approximately 1 ⁇ 10 5 CFU/ml (5 ⁇ 10 4 CFU/well). The plates were incubated for 24 h at 37°C, in 5% CO 2 . After overnight growth, bacteria (10 ⁇ l of suspension from each well) were plated onto GCB agar and further incubated for another 24 h at 37°C, in 5% CO 2 . The MIC was defined as the lowest concentration of an antimicrobial that prevented visible growth on GCB agar plates. Time-kill curve analysis of antimicrobials against N.
  • gonorrhoeae Method for time-kill curve analysis was adapted from Foerster et al. (Time-kill curve analysis and pharmacodynamic modelling for in vitro evaluation of antimicrobials against Neisseria gonorrhoeae. BMC Microbiol 16, 216 (2016)).
  • the inoculum of N. gonorrhoeae strains was prepared in sterile PBS from cultures grown on GCB agar plates for 16–18 h at 37 °C, 5 % CO 2 . Bacterial suspensions in PBS were adjusted to OD A600 nm of 1.0 (equivalent to approximately 1 ⁇ 10 9 CFU/ml bacteria).
  • bacterial suspensions were diluted 1:10 into GW medium and 30 ⁇ l of this inoculum was diluted in 7.5 ml pre-warmed (37 °C) GW medium.
  • 90 ⁇ l per well of this bacterial suspension was dispensed in round bottom 96-well NunclonTM microtiter plates (ThermoFisher scientific). The plates were pre-incubated for 3 h shaking at 150 r.p.m, 37 °C, 5 % CO 2 .
  • 110 ⁇ l of the antimicrobial diluted in GW medium or GW medium alone for a negative control was added to each well.
  • Inoculum for mAb:peptide assays was prepared in GW medium which had been harvested from the respective bacterial strain grown for 24 h at 37 °C, 5 % CO 2 , prior to dialysis with slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) into fresh GW medium to retain IgAP.
  • Haemolysis assay Haemolytic activity of Oct-TriA 1 analogues and APC’s was performed as previously described (Oddo, A. & Hansen, P. R. Hemolytic Activity of Antimicrobial Peptides. Methods Mol Biol 1548, 427-435 (2017)).
  • Peptides were added to 96-well V-bottomed polypropylene plates in two-fold dilutions (7 concentrations, 75 ⁇ l) with a final starting concentration of 200 ⁇ g/ ml or 2.8 mg/ ml; APCs were added to the wells at a final concentration of 1.4 mg/ ml.
  • Mellitin 2.5 ⁇ M was added as a positive control and PBS was added to negative control wells. Each sample and control were tested in triplicate. An equal volume of erythrocytes was added to each well and incubated at 37 °C for 1 h.
  • Erythrocytes were subsequently pelleted at 1,000 ⁇ g for 10 minutes and supernatant (60 ⁇ l) transferred to 96-Well flat-bottomed polystyrene plates and absorbance was read at OD 415 nm. Positive and negative controls were averaged and normalised to 100 and 0% haemolysis respectively; Percent haemolysis of peptides and APCs were calculated relative to the positive control.
  • Cytotoxicity assay Cell culture For the cytotoxicity assays, HK-2 cells (CRL-2190TM; American Type Culture Collection) were seeded 24 hours prior to addition of Oct-TriA 1 analogues or APCs in 96-well plates at a density of 2 ⁇ 10 4 cells/ well for approximately 80% confluency. Sample preparation: Oct-TriA 1 analogues and APCs were added into each well with a final concentration gradient from 400 ⁇ g/ ml and 5.6 mg/ ml, to 25 ⁇ g/ ml and 350 ⁇ g/ ml in 2-fold dilutions, respectively. Each sample was performed in triplicate.
  • said protease recognition site is a group of formula [PRS], wherein said group of formula [PRS] is a group of formula [PRS1] or [PRS2]: Yaa – Pro – Xaa – Pro [PRS1] Gly – Gly– Ala [PRS2] wherein: Yaa is selected from Arg-Pro; Thr-Pro; Ala-Pro; Gly-Pro; and Pro; and Xaa is selected from Thr; Ser and Ala. 6.
  • each Aaa which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; each Baa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; n is an integer from 1 to 10; preferably from 1 to 6 and m is an integer from 1 to 10; preferably from 1 to 6. 7.
  • - X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta- alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2-aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13- tetraoxapenta-decanoic acid); preferably O2Oc; - Y is absent or is selected from O2Oc (8-amino-3,6-
  • An antimicrobial agent comprising a group of formula (III): D – X – Aaa1 – Aaa2 – Aaa3 – [PRS] – Baa1 – Baa2 – Baa3 – Y – Caa (III) wherein: - Aaa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Met, Ala, Ser, Thr,
  • - X is absent or is O2Oc (8-amino-3,6-dioxaoctanoic acid), PEG3 (12-amino-4,7,10- trioxadodecanoic acid) or PEG4 (15-amino-4,7,10,13-tetraoxapenta-decanoic acid); preferably O2Oc;
  • - Aaa1 is selected from Val, Leu, Pro, and Arg;
  • - Aaa2 is selected from Val, Leu, Pro, and Arg;
  • - Aaa3 is absent or is selected from Val, Leu, Pro and Arg;
  • - Baa1 is selected from Val, Ala, Gln, Asn, Phe, and Ser,;
  • - Baa2 is selected from Val, Ala, Gln, Asn, Phe, and Ser;
  • - Baa3 is selected from Val, Ala, Gln, Asn, Phe, and Ser; and
  • an antimicrobial agent according to any one of the preceding aspects, wherein the antimicrobial moiety is an antibiotic compound.
  • the antibiotic compound is selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides. 13.
  • an antimicrobial agent according to any one of the preceding aspects, wherein the antimicrobial moiety is an antimicrobial peptide which is a N-acylated tridecapeptide or N- acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C 4-12 alkyl, C 4-12 alkenyl, or C 4-12 alkynyl group which is unsubstituted or which is substituted with 1, 2 or 3 substituents selected from CO, -OR a , -N(R a ) 2 , halogen, and -CN and each R a which may be the same or different is selected from H and unsubstituted C 1-2 alkyl, preferably H.
  • an antimicrobial agent according to any one of aspects 12 to 13, wherein the antimicrobial peptide is octyl-tridecaptin A1 or a variant thereof comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1.
  • An antibody capable of specifically binding to MtrE comprising: (a) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 22 to 24 and 26 to 28, respectively; (b) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 2 to 4 and 6 to 8, respectively; or (c) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 12 to 14 and 16 to 18, respectively. 16.
  • An antimicrobial agent according to any one of aspects 1 to 14, wherein the microbe-targeting moiety is an antibody according to any one of aspects 15 to 17.
  • - said bacterial infection is caused by Neisseria gonorrhoeae (N gonorrhoeae) or Neisseria meningitides (N meningitides), preferably N gonorrhoeae; or - said bacterial infection is caused by antibiotic resistant Neisseria gonorrhoeae, preferably Multi-Drug Resistant Neisseria gonorrhoeae. 25.
  • a protease-cleavable oligopeptide comprising a group of formula (Aaa) n – [PRS] – (Baa) m – Y – Caa wherein - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on a microbe-targeting moiety such as an antibody; and - [PRS], (Aaa), (Baa), n, m and Y are as defined in any one of aspects 6 to 14. 27.

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Abstract

The present invention provides an antimicrobial agent and uses thereof.

Description

Product Field of Invention The invention relates to antimicrobials, and methods and uses thereof. The agents of the invention are particularly useful in treating infections by pathogenic bacteria such as N. gonorrhoeae. Background to the Invention Antimicrobials, such as antimicrobial peptides (AMPs), have attracted great interest in clinical research as potential therapeutic agents against microbes, such as multidrug resistant bacteria. However, the non-specificity of AMPs combined with the potential toxic side effects, such as haemolytic activity, hamper their clinical development. Neisseria gonorrhoeae is a Gram negative; obligate human pathogen, which is the causative agent of the sexually transmitted infection gonorrhoea. Complications can arise from untreated gonococcal infection including pelvic inflammatory disease, ectopic pregnancy, and infertility, as well as increased transmission and acquisition of HIV. N. gonorrhoeae has developed mechanisms to avoid host-mediated innate immune defence and clinical isolates typically exhibit high levels of antimicrobial resistance such as azithromycin resistance. It is an object of the invention to identify further and improved antimicrobials, in particular against drug-resistant microbes, such as N. gonorrhoeae, for treating and preventing infections with reduced toxicity against host cells. Summary of the Invention The inventors have recognised the need to selectively kill pathogenic microbes such as pathogenic bacteria whilst minimising non-selective cell killing. Unfortunately, many known antimicrobial agents are insufficiently selective to be used to treat the most difficult infections without causing significant side effects arising from non-selective cell killing. This is particularly the case when the pathogenic microbes are resistant to conventional antimicrobial agents. In this case available agents for treating such infections are typically highly toxic and generally non-selective. Accordingly, unwanted side effects are particularly prevalent when treating patients infected by antimicrobial drug resistant pathogens. In view of this, the inventors have developed novel selective antimicrobial agents. The antimicrobial agents of the invention are capable of selectively binding to and being activated by a pathogenic microbe. In the presence of the pathogenic microbe, the antimicrobial activity of the agent is activated. In the absence of the pathogenic microbe, the agent has reduced activity. Thus, the agent is selective for the pathogenic microbe. As such, it can be used to treat infection by the pathogenic microbe whilst minimising side effects arising from off-target activity. One pathogenic microbe of particular interest is the pathogenic bacteria N. gonorrhoeae. The inventors have developed novel antimicrobials that specifically target N. gonorrhoeae, which are activated in the presence of the protease secreted by N. gonorrhoeae, immunoglobulin A1 proteases (IgAP). In particular the inventors generated an antibody-peptide conjugate (APC) consisting of an anti- N. gonorrhoeae antibody specific for MtrE that is covalently linked to the antimicrobial peptide (AMP), Oct-TriA1, using an IgA protease-cleavable linker. As shown in the Examples, modification of the C- terminus of Oct-TriA1 with two IgAP cleavable linkers still displayed excellent antimicrobial activity but not when bound to the MtrE mAb. Furthermore, Oct-TriA1 was cleaved from the APC and displayed potent antimicrobial activity against multidrug resistant N. gonorrhoeae. Interestingly, the inventors found that conjugation of Oct-TriA1 impairs its toxicity against human cells, including reduced haemolytic activity against human RBCs, as well as markedly reduced cytotoxicity against human renal cells. Without wishing to be bound by theory, the antimicrobial agent of the invention is capable of selectively targeting a microbe of interest because of the presence of a microbe- targeting moiety and of an anti-microbial moiety which is released and becomes active only in the presence of a protease secreted by said microbe. When the antimicrobial agent is not in proximity of the microbe of interest, the antimicrobial moiety has reduced activity as it is bound to a microbe-targeting moiety. However, when the antimicrobial agent is brought into the proximity of the microbe of interest by the microbe-targeting moiety, the linker is cleaved by the protease secreted by the microbe of interest, and the antimicrobial moiety is released from the microbe-targeting moiety and becomes active. The invention is not however limited to treatment of infection by bacteria such as N. gonorrhoeae. The invention provides a broader approach to treating infection by pathogenic microbes and is readily applied in treating a wide range of infections, with advantages as set out herein. Accordingly, provided herein is an antimicrobial agent comprising a) a microbe-targeting moiety; b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker. In some embodiments the microbe expresses one or more proteins such as one or more proteases, and the linker is capable of being cleaved by said one or more proteins (e.g. proteases). In some embodiments the antimicrobial moiety is an antibiotic compound e.g. an antibiotic compound selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides. In some embodiments the antimicrobial moiety is an N-acylated tridecapeptide or N-acylated tridecalipopeptide (e.g. TriA1), such as Oct-TriA1. In some embodiments the microbe is a bacterium, such as a bacterium of family Neisseriaceae (e.g. Neisseria gonorrhoeae). In some embodiments the microbe-targeting moiety is an antibody. In some embodiments the antibody is capable of specifically binding to MtrE. Also provided is an antibody as described in more detail herein. Also provided is a combination of antibodies as described herein. Also provided are one or more polynucleotides encoding the antibody described herein, one or more vectors comprising said polynucleotides, or a host cell comprising said vectors. Also provided is a method for producing an antibody as described herein. Also provided is a pharmaceutical composition comprising the antimicrobial agent and/or the antibody provided herein.. Also provided is an agent as described in more detail herein (e.g. an antimicrobial agent as described herein or an antibody as described herein) for use in medicine. The agent may be for use in treating or preventing bacterial infection in a subject in need thereof. Also provided is protease-cleavable oligopeptide (e.g. a linker) as described in more detail herein. Also provided is a kit, comprising an antimicrobial agent or an antibody as provided herein, together with instructions for use. Also provided is a method of making an antimicrobial agent as described herein, comprising conjugating an antimicrobial moiety to a microbe-targeting moiety (e.g. an antibody as described herein ) via a linker, wherein said linker is selectively cleavable by said microbe. Also provided is the use of a protease-cleavable oligopeptide as described in more detail herein to conjugate a microbe-targeting moiety to an antimicrobial moiety. Also provided is a method of identifying the presence of bacteria (e.g. N. gonorrhoeae) or a protein or a protein fragment thereof, in a sample using said antibody. These and further aspects of the invention are described in more detail herein. Brief Description of the Figures Figure 1: mAbs recognise MtrE in all tested N. gonorrhoeae strains. (a,b) Flow cytometry analysis of MtrE mAb binding to WT strains; FA1090, and MS11 (solid line) with isogenic ΔMtrE (dotted line) mutants shown. (c) Western blot analysis of MtrE mAb binding to all clinical N. gonorrhoeae strains selected from a variety of core genome groups tested. Recombinant MtrE along with WT gonococcal strains, FA1090 and MS11 with isogenic ΔMtrE used as mAb controls Figure 2: APC design and characterisation. (a) Model of APC (not drawn to scale) comprising an anti-MtrE mAb, conjugated to an IgAP cleavable linker and Oct- TriA1 antimicrobial peptide via a C-terminal cysteine (b) MALDI-TOF mass spectrometry analysis of MtrE mAb (mAb 184a-D10), and MtrE mAb covalently linked to PRN2028, PRN2029. Change in mass, compared to MtrE mAb indicates approximately 7-8 peptides per APC. Flow cytometry analysis of MtrE mAb (black) or APCs conjugated to PRN2028 (blue), PRN2029 (green) and PRN2208 (orange) binding to FA1090 (c), MS11 (d) and G97687 (e). Figure 3: APC linker is cleaved in the presence of IgAP. (a) IgAP cleavage of hIgA1 in supernatant from WT MS11, FA1090, G97687 with isogenic ΔIgAP and ΔMtrE mutants. hIgA1 incubated in GW media or PBS used as a negative control for cleavage. hIgA1 heavy chain (Hc) and light chain (Lc) along with hIgA1 cleavage product (Cp) indicated. Mass spectrometry analysis of released PRN1967 (b; indicated by box) or PRN1968 (c; indicated by box) peptide from APC after incubation in supernatant from WT FA1090 but not in FA1090ΔIgAP supernatant. PRN1968 and PRN1969 in PBS shown as a mass spectrometry control. Figure 4: OctTriA1 analogues cleaved from APC by IgAP are bactericidal. (a) Time to kill curve analysis protocol. N. gonorrhoeae were grown for 24 hours prior to harvesting supernatant containing IgAP. Supernatant was dialysed into fresh media prior to inoculating with respective N. gonorrhoeae strains. After 3 hours growth, APCs or peptides were added and CFU/ ml was calculated from 30 minute time-points. (b, c) Dose- dependant time to kill analysis of PRN1967 (b) and PRN1968 (c) of FA1090. No peptide shown in red with increasing concentrations of peptide from 0.1 μg/ ml (light blue) to 100 μg/ ml (dark blue). Values are mean ± s.d. of CFU/ ml (n > 2) (d, e) Time to kill curve analysis of APCs conjugated to PRN2028 (d) and PRN2029 (e) with FA1090 (red), isogenic ΔIgAP (black) and ΔMtrE (blue) treated with approximately 10x MIC of peptides (50 μg/ ml). No APC (solid line) and APC (dashed line), values are mean ± s.d. of CFU/ ml (n > 2). (f) Time to kill curve analysis of APCs conjugated to PRN2028 (green), PRN2029 (blue) and PRN2208 (orange) with unconjugated mAb (black) with MDR clinical isolate G97687 which has mutations resulting in increased MtrE expression (peptides at a concentration of 50 μg/ ml). Figure 5: Hemolytic and cytotoxic activity of Oct-TriA1 analogues and APCs. (a, b) Hemolysis of human erythrocytes by (a) Oct-TriA1 (red), APCs conjugated to PRN2028 (green), PRN2029 (blue) PRN2208 (orange) or unconjugated mAb (black). Erythrocytes were incubated in two-fold dilutions of peptide starting from 200 µg/ ml. (b) Hemolysis of Oct-TriA1 analogues, PRN1967 (green) and PRN1968 (blue), with C- terminal extensions which are the result of IgAP cleavage. Erythrocytes were incubated in two-fold dilutions of peptide starting from 1 mg/ ml. Values expressed as percentage hemolysis relative to erythrocytes incubated with 2.5 µM mellitin (100%) and PBS (0%), mean ± s.d. (n>3). (c-h) Evaluation of cytotoxicity of Oct-TriA1 analogues and APCs against HK-2 cells which are derived from a normal, human kidney proximal tubular cells. (c) LDH release assay after 4 hours from HK-2 cells after exposure to two-fold dilutions of peptide starting from 400 µg/ ml; Oct-TriA1 (red), PRN1967 (green) and PRN1968 (blue). (d) Cell metabolic activity was assessed using MTT assay from the reduction of MTT into formazan after HK-2 cells were exposed for 4 hours to two-fold dilutions of peptide starting from 400 µg/ ml; Oct-TriA1 (red), PRN1967 (green) and PRN1968 (blue). (e) Half maximal effective concentration (EC50) for release of LDH after exposure to Oct-TriA1 (red), PRN1967 (green) and PRN1968 (blue) at 4, 24 and 48 hours. (f) Half maximal effective concentration (EC50) for cell viability by measurement of MTT reduction after exposure to Oct-TriA1 (red), PRN1967 (green) and PRN1968 (blue) at 4, 24 and 48 hours. (g) LDH release assay after 4 hours from HK-2 cells after exposure to two-fold dilutions of APCs starting from 5.6 mg/ ml; APCs conjugated to PRN2028 (green), PRN2029 (blue) and PRN2208 (orange). (h) Cell metabolic activity using MTT after exposure to two-fold dilutions of APCs starting from 5.6 mg/ ml; APCs conjugated to PRN2028 (green), PRN2029 (blue) and PRN2208 (orange). Figure 6: OctTriA1 IgAP linker is cleaved in the presence of IgAP. Structure of OctTriA1 analogues with IgAP linker, peptide number PRN2028 (a) and PRN2029 (b). Cleavage product indicated in red resulting in the liberated peptide PRN1967 and PRN1968 respectively. Spacer (blue) between antimicrobial OctTriA1 and IgAP linker. Mass spectrometry analysis of IgAP cleavage of peptides PRN2028 (c, box with solid line) and PRN2029 (d, box with solid line) to PRN1967 (c, box with dotted line) and PRN1968 (d, box with dotted line) after incubation in supernatant from WT MS11 but not in MS11ΔIgAP supernatant. PRN2028 and PRN2029 along with FB media alone shown as a mass spectrometry controls. Figure 7: APC linker is cleaved by FA1090 IgAP. Mass spectrometry analysis of released PRN1967 (a, blue peak) and PRN1968 (b, green peak) peptide from APC after incubation in supernatant from WT FA1090 but not in FA1090ΔIgAP supernatant. PRN1968 and PRN1969 in PBS as well as supernatant from FA1090 and FA1090ΔIgAP shown as a mass spectrometry controls. Figure 8: OctTriA1 analogues are bactericidal after cleavage by the IgAP from isolates with upregulated MtrE. (a-d) Dose-dependent time to kill analysis of PRN1967 (a, b) and PRN1968 (c, d) of MS11 (a, c) and G97687 (b, d). No peptide shown in red with increasing concentrations of peptide from 0.1 μg/ ml (light blue) to 100 μg/ ml (dark blue). Values are mean ± s.d. of CFU/ ml (n > 2) (e-g) Time to kill curve analysis of APCs conjugated to PRN2028 (e), PRN2029 (f) and PRN2208 (g) with MS11 (red), isogenic ΔIgAP (black) and ΔMtrE (blue) treated with approximately 10x MIC of peptides (50 μg/ ml). No APC (solid line) and APC (dashed line), values are mean ± s.d. of CFU/ ml (n > 2). Figure 9: Time-course cytotoxic activity of Oct-TriA1 analogues. Evaluation of cytotoxicity of Oct-TriA1 analogues against HK-2 cells which are derived from a normal, human kidney proximal tubular cells; after exposure to two-fold dilutions of peptide starting from 400 µg/ ml; Oct-TriA1 (red), PRN1967 (green) and PRN1968 (blue). LDH release after 24 (a) and 48 hours (b). Cell viability assessed through the reduction of MTT to formazan after 24 (c) and 48 hours (d). Figure 10: Characteristics of anti-MtrE monoclonal antibodies identified in the Examples. Figure 11: Western blot analysis of MtrE mAb binding to clinical N. gonorrhoeae strains selected from a variety of core genome groups tested. Recombinant MtrE along with WT gonococcal strains, FA1090 and MS11 with isogenic ΔMtrE used as mAb controls. Figure 12: Western blot analysis of MtrE mAb binding to Neisseria meningitidis strains. Of note, mAb 184a-D10 does not cross react with N. meningitides. Recombinant MtrE was used as a mAb control. Figure 13: Surface recognition of MtrE. Flow cytometry analysis of mAbs 97a-D6 (a,b), 135a-D6 (c,d) and 184a-D10 (e,f), binding to gonococcal MtrE using strains FA1090 (blue, solid line) and MS11 (red, solid line). MS11 has mutations in the promotor region of MtrR which upregulate MtrE expression. FA1090ΔmtrE (blue, dotted line) and MS11ΔmtrE (red, dotted line) were used as negative controls. Figure 14: OctTriA1 analogues cleaved from APC by IgAP are bactericidal. (a, b) Time to kill curve analysis. Data pooled from Figure 4d-e, respectively, and an additional repeat of each of the experiments (n≥3). (c) Time to kill curve analysis of APCs conjugated to PRN2208 which contains a non-cleavable linker lacking the IgAP recognition site with FA1090, isogenic ΔIgAP and ΔMtrE treated with approximately 10x MIC of peptides (50 μg/ ml). (d) Time to kill curve analysis of APCs conjugated to PRN2028 (▼), PRN2029 (●) and PRN2208 (▲) or unconjugated mAb (■) with MDR clinical isolate G97687 which has mutations resulting in increased MtrE expression (peptides at a concentration of 150 μg/ ml). Figure 15: Hemolytic and cytotoxic activity of Oct-TriA1 analogues and APCs. (a-f) Evaluation of cytotoxicity of Oct-TriA1 analogues and APCs against HK-2 cells and End1/E6E7 cells. Data pooled from Figure 5c-h, respectively, and a repeat of each of the experiments in End1/E6E7 human cervical endothelial cells (n≥3). (c,d) p values are indicated between peptides at 4 hr time point. Figure 16: OctTriA1 analogues are bactericidal after cleavage by the IgAP from isolates with upregulated MtrE. (a-d) Dose dependent time to kill analysis. Data pooled from each of Figure 8a-d, respectively, and a repeat of each of the experiments (n≥3). Detailed Description of the Invention Antimicrobial As discussed above, the invention provides a) a microbe-targeting moiety; b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker. As discussed in more detail below, the microbe-targeting moiety can be any suitable moiety for targeting the microbe of interest. For example, the agent can be designed to target a pathogenic microbe responsible for microbial infection in a subject. The microbe-targeting moiety can thus be designed or selected to target the pathogenic microbe. The microbe-targeting moiety selectively targets the microbe of interest in preference to other available targets. The microbe-targeting moiety may for example selectively target or bind to an epitope on the target microbe. The epitope may be present or expressed on the surface of the target microbe. The epitope may for example be a specific protein expressed by the target microbe on the surface of the target microbe. The microbe-targeting moiety may for example be an antibody as described herein which selectively binds to the epitope on the target microbe. The antimicrobial moiety can be any suitable agent which has antimicrobial activity. The antimicrobial moiety is typically a chemical compound for example an antibiotic compound. The antimicrobial moiety may be an oligopeptide or derivative thereof. Suitable antimicrobial moieties are described in more detailed herein. In the antimicrobial agent, the antimicrobial moiety is conjugated to the microbe- targeting moiety by a linker. The linker is configured or chosen to be cleavable by the microbe which the antimicrobial agent is designed to target. The linker is typically selectively cleavable by the microbe which the antimicrobial agent is designed to target. In other words, the cleavage of the linker is retarded or substantially or wholly prevented when the microbe which the antimicrobial agent is designed to target is absent; and the linker is substantially or wholly cleaved or cleaved more rapidly when the microbe which the antimicrobial agent is designed to cleave is present. For example, the linker may be selectively cleaved by a protein e.g. an enzyme which is produced (e.g. expressed) by the microbe which the antimicrobial agent is designed to target, but which is not produced by other cells. This is described in more detail herein. As described in more detail here, the antimicrobial agent provided herein is useful in treating or preventing bacterial infection caused by the microbe which the antimicrobial agent is designed to target. This is described in more detail as follows. The antimicrobial agent comprises a microbe-targeting moiety which targets the antimicrobial agent to the target microorganism. For example, the microbe-targeting moiety may bind preferentially to one or more epitopes on the target microorganism. The linker of the antimicrobial agent is selectively cleavable in the presence of the target microorganism. The target microbe typically expresses one or more proteins which are capable of cleaving said linker. The one or more proteins may be for example one or more proteases. Suitable proteases which are expressed by exemplary target microbes are described in more detail herein. Proteases are specifically preferred when the linker comprises a peptide comprising protease recognition sequence specific for said protease. As described in more detail herein, it is within the capacity of one of skill in the art to generate microbe-targeting moieties such as antibodies which are capable of binding to a target microorganism, e.g. to a protein expressed on the surface of a target microbe. Proteases which are expressed by target microbes can be readily assessed in order to identify their consensus cleavage recognition sequence. This can be done using techniques routine in the art, as described in more detail herein. The recognition sequence for a specific protease can be readily determined allowing a linker to be chosen or designed that can be cleaved by said protease. In other words, selection of a target microbe allows the combination of (i) a specific microbe-targeting moiety and (ii) a specific protease recognition sequence to be readily identified such that the antimicrobial agent of the invention can be readily constructed. Selection of a target microbe for targeting with the antimicrobial agent of the invention is a parameter which can be determined by the user of the invention. The microbe which is targeted by the antimicrobial agent provided herein selectively cleaves the cleavable linker. The cleavable linker is selectively cleaved in the presence of the microbe. The cleavable linker is selectively cleaved in the vicinity of the microbe. Attachment or association of the microbe-targeting moiety of the antimicrobial agent to the target microbe ensures that the cleavable linker is maintained in the vicinity of the target microbe. The cleavage of the linker by the target microbe releases the antimicrobial moiety. The antimicrobial moiety is thus released in the presence of the target microbe. The antimicrobial moiety interacts with the target microbe and exerts an antimicrobial effect on the target microbe, e.g. by killing the target microbe, preventing replication or division of the target microbe, etc. The activity of the antimicrobial moiety is not limited in the invention, and any suitable antimicrobial moiety can be used. Often the antimicrobial moiety is an antimicrobial peptide such as an antibiotic peptide. Often the linker comprises an oligopeptide. The antimicrobial peptide and the linker can thus be synthesized as a single moiety, e.g. via solid-phase peptide synthesis. Solid-phase peptide synthesis methods are well known by those of skill in the art and peptide-synthesis is commercially available as a service. However, the invention is not limited to the use of peptide linkers and/or antimicrobial moieties. Surprisingly, the inventors have found that conjugating the antimicrobial moiety to a microbe-targeting moiety using a linker as described herein often reduces the toxicity the antimicrobial moiety compared to the same antimicrobial moiety which is not conjugated to the microbe-targeting moiety. Accordingly, the antimicrobial moiety can be selectively delivered to the site of infection by the microbe with minimal or no off-target side effects. Only once selectively cleaved by the target microbe is the activity of the antimicrobial moiety restored and the antimicrobial moiety can then exert its antimicrobial activity against the microbe. Accordingly, in one embodiment the invention provides a method of reducing the toxicity of an antimicrobial moiety as described herein, comprising conjugating the antimicrobial moiety to an microbe-targeting moiety using a linker as described herein. In another embodiment the invention provides a method of improving the selective killing of microbes such as bacteria, comprising contacting said microbes with a antimicrobial agent of the invention. As described in more detail in the examples, the activity of the antimicrobial agent is typically synergistic: the design of the antimicrobial agent provided herein provides the combined benefits of targeting a target microbe, avoiding side effects arising from off- target toxicity of the antimicrobial moiety, and selectively delivering the antimicrobial moiety to the site of infection by the microbe. Furthermore, by binding to the microbe the microbe-targeting moiety of the antimicrobial agent may provide a further antimicrobial activity. Microbe-targeting moiety/Antibody As discussed above, the antimicrobial agent provided herein comprises a microbe- targeting moiety. A microbe-targeting moiety useful with the invention is capable of specifically binding to a target microbe and/or a fragment thereof. Typically, the microbe- targeting moiety specifically binds to the target microbe and/or a fragment thereof with high affinity. The microbe-targeting moiety may be a protein or a mixture of proteins, but may also be an aptamer, affimer, molecularly imprinted polymer (MIP), or a nucleic acid. The microbe-targeting moiety is typically an antibody, such as an antibody as described herein. The target microbe may be any microbe, such as a bacteria, a virus, a fungus or a parasite. The bacteria may be Neisseriaceae (e.g. N.gonorrhoeae or N. meningitis), Haemophilus (e.g. Haemophilus influenzae type b) or Streptococcus (e.g. Streptococcus pneumoniae). The target virus may be influenza, coronavirus, norovirus, or hepatitis A virus. The bacteria may be resistant to antibiotics, e.g. cephalosporins and/or macrolide antibiotics. Antibiotics to which the bacteria may exhibit resistance are described in more detail herein. The bacteria may be a Gram negative bacteria. The bacteria may be of family Neisseriaceae, Pasteurellaceae or Pseudomonaceae. The bacteria may be of family Neisseriaceae, Streptococcaceae, or Pasteurellaceae. The bacteria may be a Gram positive bacteria, such as from family of Streptococcaceae. The bacteria may be of family Neisseriaceae. The bacteria may be Neisseriaceae gonorrhoeae (N. gonorrhoeae). The N.gonorrhoeae may be any strain, such as FA1090, FA19, MS11, F62, WHO-F (NCTC 13477), WHO-G (NCTC 13478), WHO-K (NCTC 13479), WHO-L (NCTC 13480), WHO-M (NCTC 13481), WHO-N (NCTC 13482), WHO-O (NCTC 13483), WHO-P (NCTC 13484), WHO-U (NCTC 13417), WHO-V (NCTC 13418), WHO-W (NCTC 13419), WHO-X (NCTC 13420), WHO-Y (NCTC 13421), or WHO-Z (NCTC 13411), or variants thereof. The N.gonorrhoeae may be multidrug resistant. The N.gonorrhoeae strain may not express functional PIA and/or PIB (encoded by PorA and PorB, respectively). For example, PIA and/or PIB may be absent, or the PorA and/or PorB genes may comprise one or more mutations. The microbe-targeting moiety may be specific for any epitope in a target microbe. The epitope may be in any protein specifically expressed in the target microbe. The protein may be a surface protein. The protein may be a lipopeptide. In the embodiment where the target microbe is N.gonorrhoeae, the microbe- targeting moiety may be specific for NGO0901, NGO0439 (LolB), NGO2047, NGO0277 (ComL), NGO1780 (BamE), NGO2139 (MetQ), NGO0994 (Laz), NGO1225 (peptidyl- prolyl cis-trans isomerase), NGO1363 (MtrE), NGO1559 (OmpA), NGO1276 (AniA), NGO1393 (mafA2), or NGO1067 (mafA1). The microbe-targeting moiety may be specific for MtrE. MtrE forms part of the MtrCDE tripartite multidrug efflux pump, which is found in for example N.gonorrhoeae and N.meningitis. The microbe-targeting moiety (e.g. an antibody) may be specific for MtrE in N.gonorrhoeae. The microbe-targeting moiety (e.g. an antibody) may not cross react with N.meningitis, such as any of the antibodies described below. It is within the teaching herein that the microbe-targeting moiety may be fused to an affinity tag for protein purification e.g. HA-tag which correspond to amino acids 98 to 106 of human influenza hemagglutinin, polyhistidine (His), c-myc and FLAG. The affinity tag may be fused to the N- or C-terminal of the microbe-targeting moiety, for example. Antibody The invention also provides antibodies specific for N.gonorrhoeae. The antibody may be useful as the microbe-targeting moiety of the antimicrobial agent of the invention. Hence, the microbe-targeting moiety of the antimicrobial agent of the invention may comprise or consist of an antibody of the invention. Thus, an antimicrobial agent of the invention may comprise a) an antibody specific for a microbe, b) a linker selectively cleavable by said microbe, and c) an antimicrobial moiety, wherein the microbe-targeting moiety is conjugated to the antibody by the linker. The antibody may be capable of specifically binding to MtrE. For example, the anti-MtrE antibody may comprise at least three, four, five, or all six CDRs: CDRH1 (GFSLTRYGVH), CDRH2 (VIWSDGTTTYNSALKS), CDRH3 (GTSAYYGNNDAMVF), CDRL1 (LASGNIHNYLA), CDRL2 (NAKTLAD) and CDRL3 (QHFWTSPFT), as set out in SEQ ID NOs: 22-24 and 26-28, respectively (according to the KABAT numbering system). The antibody may comprise at least one, at least two or all three heavy chain CDRs (CDRHs). The antibody may comprise at least one, at least two or all three light chain CDRs (CDRLs). The antibody typically comprises all six (i.e. three heavy and three light chain) CDRs. The antibody of the invention may comprise a heavy chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 21 (QVQLKESGPGLVAPSQNLSITCTVSGFSLTRYGVHWVRQPPGKGLEWLVVIWSD GTTTYNSALKSRLSISKDNSKSQVFLKMNRLQTDDAAMYYCARGTSAYYGNNDA MVFWGQGTSVTVSS), and/or a light chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 25 (DIQMTQSPASLSASVGETVTITCLASGNIHNYLAWYQQKQGKSPQLLVYNAKTLA DGVPSRFSGSGSGTQYSLKINSLQPEDFGSYYCQHFWTSPFTFGSGTKLEIQ). As shown in the Examples, an antibody comprising these sequences, mAb184a-D10, is capable of specifically binding to MtrE in N.gonorrhoeae. This antibody does not cross react with MtrE in N.meningitis. Hence, an antibody of the invention may be capable of specifically binding to MtrE in N.gonorrhoeae. The antibody of the invention may not cross react with MtrE in N.meningitis. The anti-MtrE antibody may comprise at least three, four, five, or all six CDRs: CDRH1 (GFTFTDYNIH), CDRH2 (YFFPYNGGSAYNPKFKN), CDRH3 (DGEIMRAMDS), CDRL1 (KSSQSLFNSGNQKNYLT), CDRL2 (WTSTRES) and CDRL3 (QNDFSYPFT) as set out in SEQ ID NOs: 12-14 and 16-18, respectively (according to the KABAT numbering system). The antibody may comprise at least one, at least two or all three heavy chain CDRs (CDRHs). The antibody may comprise at least one, at least two or all three light chain CDRs (CDRLs). The antibody typically comprises all six (i.e. three heavy and three light chain) CDRs. The antibody of the invention may comprise a heavy chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 11 (DVQLQQSGPDLVKPGASVKMSCKASGFTFTDYNIHWVKQSHGKSLEWIGYFFPY NGGSAYNPKFKNKATLTVDHSSSTAYMELRSLTSEDSAVYYCARDGEIMRAMDS WGQGTSVTVSS), and/or a light chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 15 (DIVMTQSPSSLTVTTGETVTMSCKSSQSLFNSGNQKNYLTWYQQKPGQSPKLLIY WTSTRESGVPDRFTGSGSGTDFTLTIRNVQAEDLAVYYCQNDFSYPFTFGSGTKLE IK). As shown in the Examples, an antibody comprising these sequences, mAb97A-D6, is capable of specifically binding to MtrE in N.gonorrhoeae or N. meningitis. The anti-MtrE antibody may comprise at least three, four, five, or all six CDRs: CDRH1 (GFTFNDYYMY), CDRH2 (TISYDGTDFYYPDSLKG), CDRH3 (GYYYDSSYFGV), CDRL1 (KSSQSLLNSRTRKNYLT), CDRL2 (WASTRES) and CDRL3 (KQSFNLFT) as set out in SEQ ID NOs: 2-4 and 6-8, respectively (according to the KABAT numbering system). The antibody may comprise at least one, at least two or all three heavy chain CDRs (CDRHs). The antibody may comprise at least one, at least two or all three light chain CDRs (CDRLs). The antibody typically comprises all six (i.e. three heavy and three light chain) CDRs. The antibody of the invention may comprise a heavy chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 1 (EVQLVESGGGLVKPGGSLKLSCSASGFTFNDYYMYWVRQTPEKRLEWVATISYD GTDFYYPDSLKGRFTISRDNAKNNLYLQMSSLKSEDTAIYYCARGYYYDSSYFGV WGAGTTVTVSS), and/or a light chain variable domain having an amino acid sequence with ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 5 (DIVMSQSPSSLAVSVGEKVTLSCKSSQSLLNSRTRKNYLTWYQQKPGQSPQLLIY WASTRESGVPDRFTGSGSGTDFTLTISSVQAEDLAVYYCKQSFNLFTFGGGTKLEI K). As shown in the Examples, an antibody comprising these sequences, mAb135a-D6, is capable of specifically binding to MtrE in N.gonorrhoeae or N. meningitis. The term “antibody” referred to herein includes the various antibody formats disclosed herein, including those comprising various formats of heavy and/or light chains discussed herein. The antibody may be selected from the group consisting of single chain antibodies, single chain variable fragments (scFvs), variable fragments (Fvs), fragment antigen- binding regions (Fabs), recombinant antibodies, monoclonal antibodies, fusion proteins comprising the antigen-binding domain of a native antibody or an aptamer, single-domain antibodies (sdAbs), also known as VHH antibodies, nanobodies (Camelid-derived single- domain antibodies), shark IgNAR-derived single-domain antibody fragments called VNAR, diabodies, triabodies, Anticalins, aptamers (DNA or RNA) and active components or fragments thereof. Further examples of possible antibody formats are disclosed in the review “The coming of Age of Engineered Multivalent Antibodies, Nunez-Prado et al Drug Discovery Today Vol 20 Number 5 Mar 2015, page 588-594, D. Holmes, Nature Rev Drug Disc Nov 2011:10; 798, Chan and Carter, Nature Reviews Immunology vol. 10, May 2010, 301. The antibody may comprise a complete antibody having full length heavy and light chains, or an antigen-binding fragment thereof. For example, the microbe-targeting moiety may be a full-length antibody. The antibody may be an antigen-binding fragment. An antigen-binding fragment of the invention binds to the same epitope of the parent antibody, i.e. the antibody from which the antigen-binding fragment is derived. An antigen-binding fragment of the invention typically retains the parts of the parent antibody that interact with the epitope. The antigen-binding fragment typically comprises the complementarity-determining regions (CDRs) that interact with the antigen, such as one, two, three, four, five or six CDRs. In some embodiments, the antigen-binding fragment further comprises the structural scaffold surrounding the CDRs of the parent antibody, such as the framework regions (e.g. FR1, 2, or 3) and/or the variable region domains of the heavy and/or light chains. Typically, the antigen-binding fragment retains the same or similar binding affinity to the antigen as the parent antibody. Antigen-binding fragments of antibodies include single chain antibodies (i.e. a full-length heavy chain and light chain); Fab, modified Fab, Fab', modified Fab', F(ab')2, Fv, Fab-Fv, Fab-dsFv, single domain antibodies (e.g. VH or VL or VHH), scFv. The methods for creating and manufacturing antibody fragments are well known in the art (see for example Verma et al., 1998, Journal of Immunological Methods, 216, 165-181). The antibody may be multi-valent, e.g. bivalent, trivalent or tetravalent. The multivalent antibody may comprise multiple specificities e.g bispecific or may be monospecific, see for example WO 92/22853, WO05/113605, WO2009/040562 and WO2010/035012. A multi-specific antibody comprises at least two different variable domains, wherein each variable domain is capable of binding to a separate antigen or to a different epitope on the same antigen. The constant region domains of an antibody, if present, may be selected having regard to the proposed function of the antibody molecule, and in particular the effector functions which may be required. For example, the constant region domains may be human IgA, IgD, IgE, IgG or IgM domains. Typically, the constant regions are of human origin. In particular, human IgG (i.e. IgG1, IgG2, IgG3 or IgG4) constant region domains may be used. Typically, a human IgG1 constant region. The antibody may not comprise an Fc region., i.e. may not comprise CH2 and CH3 domains. However, constant domains such as CH1, CKappa/CLambda may be present. The antibody may be an isolated antibody. An isolated antibody is an antibody which is substantially free of other antibodies having different antigenic specificities. The antibody may be a monoclonal antibody (mAb). Monoclonal antibodies (mAbs) may be produced by a variety of techniques, including conventional monoclonal antibody methodology, for example those disclosed in “Monoclonal Antibodies: a manual of techniques”(Zola H, 1987, CRC Press) and in “Monoclonal Hybridoma Antibodies: techniques and applications” (Hurrell JGR, 1982 CRC Press). Monoclonal antibodies may also be isolated from phage antibody libraries using the techniques described in, for example, Clackson et al., Nature, 352, 624-628 (1991) and Marks et al., JMol, Biol., 222(3):581-597 (1991). Monoclonal antibodies may be obtained from any suitable source. Thus, for example, monoclonal antibodies may be obtained from hybridomas prepared from murine splenic B cells obtained from mice immunized with an antigen of interest, for instance in form of cells expressing the antigen on the surface, or a nucleic acid encoding an antigen of interest. Monoclonal antibodies may also be obtained from hybridomas derived from antibody-expressing cells of immunized humans or non-human mammals such as rats, dogs, primates, etc. The antibody may be a chimeric antibody, a CDR-grafted antibody, a nanobody, a human or humanised antibody. Typically, the antibody is a human antibody. Fully human antibodies are those antibodies in which the variable regions and the constant regions (where present) of both the heavy and the light chains are all of human origin, or substantially identical to sequences of human origin, but not necessarily from the same antibody. Typically, the antibody binds to the epitope, e.g. in the with high affinity In terms of binding kinetics, an antibody of the invention may have an affinity constant (KD) value for the MtrE of N. gonorrhoeae of ≤ 100µM, ≤50µM, ≤25µM, ≤10µM, ≤1µM, ≤0.5µM, or ≤0.1µM. The KD values of some of the antibodies of the invention are provided in Figure 10. The KD value can be measured by any suitable means known in the art, for example, by ELISA or Surface Plasmon Resonance (Biacore) at 25 °C. Binding affinity (KD) may be quantified by determining the dissociation constant (Kd) and association constant (Ka) for an antibody and its target. For example, the antibody may have an association constant (Ka) of ≥ 10000 M-1s-1 , ≥ 50000 M-1s-1, ≥ 100000 M-1s-1, ≥ 200000 M-1s-1 or ≥ 500000 M-1s-1,, and/or a dissociation constant (Kd) of ≤ 0.001 s-1, ≤ 0.0005 s-1, ≤ 0.004 s-1, ≤ 0.003 s-1, ≤ 0.002 s-1 or ≤ 0.0001 s-1. The antibody may be or may comprise a modification from the amino acid sequence of an antibody described herein, whilst maintaining the activity and/or function of the antibody. The modification may a substitution, deletion and/or addition. For example, the modification may comprise 1, 2, 3, 4, 5, up to 10, up to 20, up to 30 or more amino acid substitutions and/or deletions from the amino acid sequence of an antibody described herein. For example, the modification may comprise an amino acid substituted with an alternative amino acid having similar properties. Some properties of the 20 main amino acids, which can be used to select suitable substituents, are as follows: The modification may comprise a derivatised amino acid, e.g. a labelled or non- natural amino acid, providing the function of the antibody is not significantly adversely affected. Modification of antibodies as described above may be prepared during synthesis of the antibody or by post-production modification, or when the antibody is in recombinant form using the known techniques of site-directed mutagenesis, random mutagenesis, or enzymatic cleavage and/or ligation of nucleic acids. The antibody may be a derivative that contains modification compared to a parent antibody, i.e., by the covalent attachment of any type of molecule to the antibody such that covalent attachment does not prevent the antibody from binding to the target microbe. For example, the antibody derivatives include antibodies that have been modified, e.g., by glycosylation, acetylation, PEGylation, phosphorylation, amidation, derivatization by known protecting/blocking groups, proteolytic cleavage, linkage to a cellular ligand or other protein, etc. Any of numerous chemical modifications may be carried out by known techniques, including, but not limited to specific chemical cleavage, acetylation, formylation, metabolic synthesis of tunicamycin, etc. Additionally, the derivative may contain one or more non-classical amino acids. The skilled person is readily able to determine the binding site (epitope) of an antibody using standard techniques, such as those described in the Examples of the application. The skilled person could also readily determine whether an antibody binds to the same epitope as, or competes for binding with, an antibody described herein by using routine methods known in the art. For example, to determine if a test antibody (i.e. where it is not known whether the test antibody competes with other antibodies for binding to an antigen) binds to the same epitope as an antibody described herein (referred to a “reference antibody” in the following paragraphs), the reference antibody is allowed to bind to a protein or peptide under saturating conditions. Next, the ability of a test antibody to bind to the protein or peptide is assessed. If the test antibody is able to bind to the protein or peptide following saturation binding with the reference antibody, it can be concluded that the test antibody binds to a different epitope than the reference antibody. On the other hand, if the test antibody is not able to bind to protein or peptide following saturation binding with the reference antibody, then the test antibody may bind to the same epitope as the epitope bound by the reference antibody. An antibody of the invention may bind to the same epitope or competes with any of the antibodies described herein. As well as sequences defined by percentage identity or number of sequence changes, the invention further provides an antibody defined by its ability to cross-compete with one of the specific antibodies set out herein. It may be that the antibody also has one of the recited levels of sequence identity or number of sequence changes as well. Two antibodies bind to the same or overlapping epitope if each competitively inhibits (blocks) binding of the other to the antigen. Alternatively, two antibodies have the same epitope if essentially all amino acid mutations in the antigen that reduce or eliminate binding of one antibody reduce or eliminate binding of the other. Two antibodies have overlapping epitopes if some amino acid mutations that reduce or eliminate binding of one antibody reduce or eliminate binding of the other. Additional routine experimentation (e.g., peptide mutation and binding analyses) can then be carried out to confirm whether the observed lack of binding of the test antibody is in fact due to binding to the same epitope as the reference antibody or if steric blocking (or another phenomenon) is responsible for the lack of observed binding. Experiments of this sort can be performed using ELISA, RIA, surface plasmon resonance, flow cytometry or any other quantitative or qualitative antibody-binding assay available in the art. Cross-competing antibodies can be identified using any suitable method in the art, for example by using competition ELISA or BIAcore assays where binding of the cross competing antibody to a particular epitope on the spike protein prevents the binding of an antibody of the invention or vice versa. In one embodiment, the antibody produces ≥50%, ≥60%, ≥70%, ≥80%, ≥90% or 100% reduction of binding of the specific antibody disclosed herein. Other techniques that may be used to determine antibody epitopes include hydrogen/deuterium exchange, X-ray crystallography and peptide display libraries (as described in the Examples). A combination of these techniques may be used to determine the epitope of the test antibody. Also provided herein are combinations comprising two or more antibodies of the invention, e.g. to maximise therapeutic effects and/or increase diagnostic power. For example, the invention provides a combination of antibodies comprising two or more of mAb184a-D10, mAb97A-D6 and mAb135a-D6. A combination of the antibodies of the invention may be useful as a therapeutic cocktail. Hence, the invention also provides a pharmaceutical composition comprising a combination of the antibodies of the invention, as explained further below. A combination of the antibodies of the invention may be useful for diagnosis. Hence, the invention also provides a diagnostic kit comprising a combination of the antibodies of the invention. Also provided herein are methods of diagnosing a disease or complication associated with bacteria infections in a subject, as explained further below. Protease As discussed above, the antimicrobial agent provided herein comprises an antimicrobial moiety conjugated to linker that is selectively cleavable by said microbe. Typically, the microbe expresses one or more proteins capable of cleaving said linker and said linker is cleaved by said one or more proteins. The one or more proteins may be expressed on the surface of said microbe. More often the one or more proteins are extracellular proteins. The one or more proteins may be released or secreted by the microbe into the extracellular space. The one or more proteins typically comprise one or more proteases. The proteases are typically employed by the microbe to evade the host defence system. The invention exploits these proteases by incorporating in the antimicrobial agent as described herein a peptide sequence, referred to as a linker herein, having a cleavage site recognised by such proteases. Thus, the microbe typically expresses a protease and said linker comprises a protease recognition sequence specific for said protease. The protease is typically secreted into the vicinity of the microbe. The protease is typically a serine protease. The protease may target a recognition site on a human protein. The protease may target a recognition site on a human protein such as human IgA1 (hlgA1). The protease may for example target a hinge region of said protein. The IgA protease may be a serine protease (e.g. EC 3.4.21), such as an IgA-specific serine protease (e.g. EC 3.4.21.72), a metallo protease (e.g. EC 3.4.24) e.g. an IgA-specific metallo protease (e.g. EC 3.4.24.13) or a cysteine type protease (e.g. EC 3.4.22). The IgA protease may be a serine endopeptidase (e.g. EC 3.4.21.72), which cleaves human immunoglobulin A molecules at specific proline-serine peptide bonds in the hinge region. This enzyme is secreted by Gram-negative bacteria Neisseria gonorrhoeae, Neisseria meningitidis, and Haemophilus influenza. Hence, a linker comprising this cleavage recognition site may be useful in an antimicrobial agent for targeting Neisseria gonorrhoeae, Neisseria meningitidis, or Haemophilus influenzae. For example, an antimicrobial agent of the invention may comprise: (a) a microbe-targeting moiety specific for Neisseria gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, or Gram- positive Streptococcus pneumoniae; (b) a linker comprising a cleavage recognition site for IgA serine endopeptidase (e.g. EC 3.4.21.72); and (c) an antimicrobial moiety. Examples of suitable microbe-targeting moieties, linkers and antimicrobial moieties are provided herein. The IgA protease may be a metalloendopeptidase (e.g. EC 3.4.24.13), which cleaves human immunoglobulin A molecules at specific proline-threonine peptide bonds in the hinge region. This enzyme is secreted by several pathogenic species of Streptococcus (Gram positive bacteria), e.g. S.pneumoniae. Hence, a linker comprising such a cleavage recognition site may be useful in an antimicrobial agent for targeting Streptococcus. For example, an antimicrobial agent of the invention may comprise: (a) a microbe-targeting moiety specific for Streptococcus species; (b) a linker comprising a cleavage recognition site for IgA metalloendopeptidase (e.g. EC 3.4.24.13); and (c) an antimicrobial moiety. Examples of suitable microbe-targeting moieties, linkers and antimicrobial moieties are provided herein. The IgA protease may target a recognition sequence as described herein. In some embodiments the recognition sequence targeted by the protease is an amino acid sequence comprised in a human protein such as human IgA1. In some embodiments the recognition sequence targeted by the protease is an amino acid sequence comprised in a hinge region of a human protein such as human IgA1. In some embodiments, the recognition sequence targeted by the protease is a group of formula [PRS] as described in more detail herein. In some embodiments the protease may be at least 70% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34. In some embodiments the protease is at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34. Often the protease is at least 70% identical to the amino acid sequence of SEQ ID NO: 31 or 32, preferably 31. In some embodiments the protease is at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% identical to the amino acid sequence of SEQ ID NO: 31 or 32, preferably 31. SEQ ID NO A is the amino acid sequence of the IgA serine protease expressed by N. gonorrhoeae strain FA1090. All N. gonorrhoeae isolates secrete a highly specific IgA serine protease (IgAP) which cleaves the heavy (α)-chain, in the 18-amino-acid hinge region of human IgA1 (hIgA1) as a means to subvert the host immune system. Cleavage of human IgA1 (hIgA1) by the gonococcal IgAP generates Fabα and Fcα fragments resulting in the loss of Fcα-mediated effector functions, e.g. inhibition of adherence, despite the binding activity of the Fabα fragments. Consequently, binding of the Fabα fragments may block binding of immune activating immunoglobulins therefore inhibiting complement activation and bacterial clearance. The IgA protease may target a recognition sequence which is a group of formula [PRS1] as described herein. In another embodiment the protease may be is at least 70% identical to the amino acid sequence of SEQ ID NO: 35. In some embodiments the protease is at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% identical to the amino acid sequence of SEQ ID NO: 35. SEQ ID NO 35 is the amino acid sequence of the LasA protease expressed by P. aeruginosa. The LasA protease may target a recognition sequence which is a group of formula [PRS2] as described herein. Antimicrobial moiety In the antimicrobial agent, any suitable antimicrobial moiety can be used. Typically, the antimicrobial moiety is an antibiotic compound. An antibiotic compound as used herein is a compound with antimicrobial activity against a bacterium such as a bacterium described herein. The antimicrobial activity of the antibiotic compound may be activity in killing the bacterium. The antimicrobial activity of the antibiotic compound may be activity in preventing replication or division of the bacterium. The antimicrobial activity of the antibiotic compound may be activity in preventing movement of the bacterium. The antibiotic compound may disrupt the bacterial cell wall or cell membrane. The antibiotic compound may block influx or efflux of compounds from the bacteria. The antibiotic compound may bind to a lipid on the bacterial cell membrane. The antibiotic compound may disrupt a chemical gradient across the bacterial cell membrane. The antibiotic compound may disrupt the proton motive force across the bacterial cell membrane. Without being bound by theory, antibiotic compounds which kill bacteria by disrupting the proton motive force across the bacterial cell membrane are believed to include antimicrobial peptides such as N-acylated tridecapeptides and or N-acylated tridecalipopeptides such as tridecaptic A1, described herein. The antimicrobial moiety of the antimicrobial agent may be an antibiotic compound. The antimicrobial moiety may be an antibiotic compound selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides. Examples of antimicrobial peptides are described herein. Examples of carbapenem antibiotics include Imipenem, Meropenem, Ertapenem, Doripenem and Biapenem. Examples of penicillins include Amoxicillin, Ampicillin, Ticarcillin, Piperacillin and Cloxacillin. Examples of cephalosporins include Cefazolin, Ceftriaxone, Ceftazidine and Ceftobiprole. Examples of penems include Faropenem. Examples of tetracyclines include demeclocycline, doxycycline, eravacycline, minocycline, omadacycline, sarecycline and tetracycline. Examples of quinolones include ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin and gemifloxacin. Examples of lincomycins include clindamycin and lincomycin. Examples of macrolides include azithromycin, clarithromycin, erythromycin, and fidaxomicin. Examples of sulphonamides include sulfamethoxazole, trimethoprim and sulfasalazine. Examples of glycopeptides include dalbavancin, oritavancin, telavancin and vancomycin. Examples of aminoglycosides include gentamicin, tobramycin and amikacin. Preferably, the antimicrobial moiety is an antimicrobial peptide. For example, the antimicrobial peptide may be an N-acylated tridecapeptide or N-acylated tridecalipopeptide (e.g. TriA1, TriB1, TriM1 and derivatives thereof); microcin and derivatives thereof such as microcin N, bacitracin, boceprevir, dalbavancin, daptomycin, enfuvirtide, oritavancin, teicoplanin, telaprevir, telavancin, vancomycin or guavanin (e.g. guavanin 2), a polymixin, an octapeptin, a surfactin, a lichenysin, brevicidine, lacterocidine or daptomycin. Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is a tridecaptin or an analog thereof. Tridecaptins are a group of linear cationic lipopeptides analogous to the polymyxins (Parachin, N. S. & Franco, O. L. New edge of antibiotic development: antimicrobial peptides and corresponding resistance. Front Microbiol 5, 147 (2014)). These tridecapeptides are produced by non-ribosomal peptide synthesis in Paenibacillus spp. and typically contain a mixture of both D and L amino acids as well as Diamino-butyric acid (Dab). Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is a N-acylated tridecapeptide or N-acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C4-12 alkyl, C4-12 alkenyl, or C4-12 alkynyl group which is unsubstituted or which is substituted with 1, 2 or 3 substituents selected from CO, -ORa, -N(Ra)2, halogen, and -CN and each Ra which may be the same or different is selected from H and unsubstituted C1-2 alkyl, preferably H. Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is a N-acylated tridecapeptide or N-acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C6-10 alkyl group which is unsubstituted or which is substituted with 1 or 2 substituents selected from CO, –OH, OMe and –NH2. Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is a N-acylated tridecapeptide; wherein the N terminal group with which the tridecapeptide is acylated is a C7 or C8 alkyl group which is unsubstituted or which is substituted with 1 CO substituent. For example, the N terminal group of the tridecapeptide may be acylated with an octanoyl group. Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is a N-acylated tridecapeptide comprising an N terminal group: wherein RN is the side chain of the N terminal amino acid of the tridecapeptide and the wiggly line indicates the point of attachment to the penultimate N terminal amino acid of the tridecapeptide. Preferably, when the antimicrobial agent is an antimicrobial peptide, the antimicrobial peptide is tridecaptin A1 (TriA1) or octyl-tridecaptin A1 (Oct-TriA1, also referred to herein as octanoyl-tridecaptin A1) or a variant of tridecaptin A1 or octyl- tridecaptin A1 comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1. The structure of octyl-tridecaptin A1 is shown below: TriA1 thus has the following formula: DVal-DDab-Gly-DSer-DTrp-Ser-Dab-DDab-Phe-Glu-Val-Dalle-Ala (SEQ ID NO: 36) in which the prefix D indicates the D-form of the specified amino acid (e.g. DVal is D- valine); Dab is 2,4-diaminobutyric acid; DDab is D-2,4-diaminobutyric acid; and Dalle is D-alloisoleucine. Preferably, when the antimicrobial agent is a variant of tridecaptin A1 (TriA1) or octyl-tridecaptin A1 (Oct-TriA1) comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1, said substitutions are at positions selected from positions 1, 2, 3, 4, 6, 7, 9, 10, 11 or 13 of SEQ ID NO: 36. Without being bound by theory, residues D- Dab8, D-allo-Ile12 and D-Trp5 are believed to be associated with improved antimicrobial activity. Preferably, when the antimicrobial agent is a variant of tridecaptin A1 (TriA1) or octanoyl-tridecaptin A1 (Oct-TriA1) comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1, said variant comprises from 1 to 4, preferably from 1 to 3, e.g. 1 or 2, more preferably 1 substitution in the amino acid sequence of SEQ ID NO: 36. Preferably, the antimicrobial moiety is octyl-tridecaptin A1. TriA1 peptides such as TriA1 and Oct-TriA1 have potent, selective antimicrobial activity against Gram-negative bacteria (Lohans, C. T. et al. Biochemical, structural, and genetic characterization of tridecaptin A₁, an antagonist of Campylobacter jejuni. Chembiochem 15, 243-249 (2014)). Without being bound by theory, it is believed that this activity arises as initially, cationic amino acids i.e. Dab of TriA1 interact with anionic bacterial lipopolysaccharide in the outer membrane. Next, TriA1 selectively binds the pentapeptide of Lipid II, the precursor of peptidoglycan biosynthesis, from Gram negative bacteria through interaction with the DAP residue whereby it exerts its bactericidal activity by disruption of proton motive force. Structure function studies have demonstrated that the length of the acyl tail of TriA1 is associated with its antimicrobial activity and replacement of the lipid tail with an octanoyl group (e.g. via acylation with octanoic acid) to produce Oct-TriA1 significantly lowered the minimum inhibitory concentration (MIC) against Gram negative pathogens (Cochrane, S. A. et al. Synthesis and structure-activity relationship studies of N-terminal analogues of the antimicrobial peptide tridecaptin A(1). J Med Chem 57, 1127-1131 (2014)). The antimicrobial moiety may have a cellular toxicity which is reduced by conjugation of the antimicrobial moiety to a microbe-targeting moiety as described herein. In some embodiments the toxicity (e.g. the cytotoxicity, e.g. CC50 value) of the antimicrobial moiety may be reduced by at least 10%, at least 50%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or at least 99.5% when the antimicrobial moiety is conjugated to the microbe-targeting moiety as described herein. The toxicity (e.g. the cytotoxicity, e.g. CC50 value) of the antimicrobial moiety of the antimicrobial agent may be increased by at least 50%, at least 100%, at least 200%, at least 500%, or at least 1000% when the linker conjugating the antimicrobial moiety to the microbe-targeting moiety is cleaved as described herein. CC50 values can be determined according to methods known in the art, e.g. using a sulphorhodamine assay. Cleavable linker As discussed above, the antimicrobial agent provided herein comprises an antimicrobial moiety conjugated to the microbe-targeting moiety via a cleavable linker. Any suitable linker can be used. The linker links the microbe-targeting moiety to the antimicrobial moiety and can be cleaved by the target microbe which the microbe- targeting moiety targets. Typically, the linker is or comprises a polymer. Preferably, the linker comprises a feature which allows it to be selectively cleaved by the microbe targeted by the microbe- targeting moiety. In some embodiments the linker comprises or consists of a peptide (e.g. an oligopeptide). Any suitable length of linker can be used providing it comprises a suitable cleavage site for selective cleavage by the target microbe. In some embodiments the linker comprises a peptide of from about 5 to about 50 amino acids in length. In some embodiments the linker comprises a polypeptide of from about 8 to about 20 amino acids in length. In some embodiments the linker comprises a polypeptide of from about 10 to about 15 amino acids in length. In some embodiments the linker comprises a polypeptide of about 8, 9, 10, 11, 12, 13, 14, or 15 amino acids in length. The amino acids in the linker may be directly attached e.g. by peptide bonds, or may be separated by one or more chemical spacers such as an OC(O) group. Polypeptides be readily synthesized and functionalised by those of skill in the art e.g. by solid phase peptide synthesis. In some embodiments the linker comprises a peptide of from about 5 to about 50 amino acids in length and the linker comprises a protease recognition site capable of being cleaved by a protease expressed by the target microbe. Protease recognition sites for specific proteases (e.g. proteases expressed by specific target microbes) are known in the art, and/or can be identified by screening a panel of polypeptides of varying sequence against a given enzyme to establish a consensus recognition site. In some embodiments, the linker comprises a peptide comprising a protease recognition site is a group of formula [PRS], wherein said group of formula [PRS] is a group of formula [PRS1] or [PRS2]: Yaa – Pro – Xaa – Pro [PRS1] Gly – Gly – Ala [PRS2] wherein: Yaa is selected from Arg-Pro; Thr-Pro; Ala-Pro; Gly-Pro; and Pro; and Xaa is selected from Thr; Ser and Ala. Linkers comprising a protease recognition site of formula PRS1 are particularly useful when the target microbe expresses a protease having an amino acid sequence at least 70% identical to any one of SEQ ID NOs: 31 to 34. Suitable proteases include the IgA specific serine protease proteases expressed by bacteria of family Neisseriaceae, Streptococcaceae, and Pasteurellaceae. Preferable proteases include the IgA proteases expressed by Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, and Haemophilus influenzae. More typically the protease is expressed by Neisseriaceae gonorrhoeae or Neisseria meningitides, preferably Neisseriaceae gonorrhoeae. Without being bound by theory, these proteases are believed to cleave peptides having a consensus recognition sequence of PRS1. In PRS1, Yaa is preferably selected from Ala-Pro and Pro. Most preferably Yaa is Pro. In PRS1, Xaa is preferably selected from Ser and Ala. In one embodiment Xaa is Ser. In one embodiment Xaa is Ala. Linkers comprising a protease recognition sequence of formula PRS2 are particularly useful when the target microbe expresses a protease having an amino acid sequence at least 70% identical to SEQ ID NO: 35. Suitable proteases include the LasA proteases expressed by bacteria of family Pseudomonacae, such as by P. aeruginosa. Without being bound by theory, these proteases are believed to cleave peptides having a consensus recognition sequence of PRS2. In some embodiments, the linker comprises a group of formula (I): (Aaa)n – [PRS] – (Baa)m (I) wherein: each Aaa, which may be the same or different, is independently selected from natural and non-natural amino acids each Baa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; n is an integer from 1 to 10; preferably from 1 to 6 and m is an integer from 1 to 10; preferably from 1 to 6. PRS is as defined herein, i.e. PRS may be PRS1 or PRS2 as described herein. In some embodiments, each Aaa is independently selected from L- and D- isomers of natural amino acids. In some embodiments, each Aaa is independently selected from L- isomers of natural amino acids. In some embodiments, each Aaa is independently selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys. In some embodiments, each Baa is independently selected from L- and D- isomers of natural amino acids. In some embodiments, each Baa is independently selected from L- isomers of natural amino acids. In some embodiments, each Baa is independently selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys. In some embodiments, the group of formula (I) is a group of formula (I-A) (Aaa)n – Yaa – Pro – Xaa – Pro – (Baa)m wherein each Aaa, Baa, n, m, Yaa and Xaa are as defined herein. In some embodiments, the group of formula (I) is a group of formula (I-B) (Aaa)n – Gly – Gly – Ala – (Baa)m wherein each Aaa, Baa, n, and m are as defined herein. In some embodiments the antimicrobial agent comprises a group of formula (II) D – X – (Aaa)n – [PRS] – (Baa)m – Y – Caa wherein: - D is the antimicrobial moiety; - X is absent or is a spacer group; - Y is absent or is a spacer group; - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on said microbe-targeting moiety; and - Aaa and Baa are as defined herein. In some embodiments, X is absent or is selected from O2Oc (8-amino-3,6- dioxaoctanoic acid), beta-alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2- aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino- 4,7,10,13-tetraoxapenta-decanoic acid). In some embodiments, X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10- trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta-decanoic acid). In some embodiments X is O2Oc. In some embodiments, Y is absent or is selected from O2Oc (8-amino-3,6- dioxaoctanoic acid), beta-alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2- aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino- 4,7,10,13-tetraoxapenta-decanoic acid). In some embodiments, Y is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10- trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta-decanoic acid). In some embodiments Y is O2Oc. In some embodiments, Caa is selected from Cys, Lys, Met, Ser, Thr, Arg. In some embodiments, Caa is selected from Cys and Lys. In some embodiments Caa is Cys. In some embodiments, the group of formula (II) is a group of formula (II-A) D – X – (Aaa)n – Yaa – Pro – Xaa – Pro – (Baa)m – Y – Caa wherein each D, X, Aaa, Baa, n, m, Yaa, Xaa, Y and Caa are as defined herein. In some embodiments, the group of formula (II) is a group of formula (II-B) D – X – (Aaa)n – Gly – Gly – Ala – (Baa)m – Y – Caa wherein each Aaa, Baa, n, and m are as defined herein. In some embodiments, the antimicrobial agent comprises a group of formula (III): D – X – Aaa1 – Aaa2 – Aaa3 – [PRS] – Baa1 – Baa2 – Baa3 – Y – Caa wherein: - Aaa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa3 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; In some embodiments, X is as defined for formula X. In some embodiments, X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta- decanoic acid). In some embodiments X is absent or is O2Oc. In some embodiments X is O2Oc. In some embodiments, Y is as defined for formula X. In some embodiments, Y is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta-alanine, PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13-tetraoxapenta- decanoic acid). In some embodiments Y is absent or is O2Oc. In some embodiments Y is O2Oc. In some embodiments, Aaa1 is selected from Val, Leu, Ile, Ala, Pro, Arg and Lys. In some embodiments, Aaa1 is selected from Val, Leu, Pro, and Arg. In some embodiments, Aaa1 is Val or Leu. In some embodiments, Aaa2 is selected from Val, Leu, Ile, Ala, Pro, Arg and Lys. In some embodiments, Aaa2 is selected from Val, Leu, Pro, and Arg. In some embodiments, Aaa2 is Val or Pro. In some embodiments, Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Pro, Arg and Lys. In some embodiments, Aaa3 is absent or is selected from Val, Leu, Pro and Arg. In some embodiments, Aaa3 is absent or is Arg. In some embodiments, Baa1 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa1 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa1 is Gln or Val. In some embodiments, Baa2 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa2 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa2 is Ala or Phe. In some embodiments, Baa3 is selected from Val, Leu, Ile, Ala, Gln, Asn, Phe, Tyr, Ser, Thr, and Met. In some embodiments, Baa3 is selected from Val, Ala, Gln, Asn, Phe, and Ser. In some embodiments, Baa3 is Asn or Ser. In some embodiments, the group of formula (III) is a group of formula (III-A) D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 – Y – Caa wherein each D, X, Aaa1, Aaa2, Aaa3, Baa1, Baa2, Baa3, Yaa, Xaa, Y and Caa are as defined herein. In some embodiments, the group of formula (III) is a group of formula (III-B) D – X – Aaa1 – Aaa2 – Aaa3 – Gly – Gly – Ala – Baa1 – Baa2 – Baa3 – Y – Caa wherein each D, X, Aaa1, Aaa2, Aaa3, Baa1, Baa2, Baa3, Yaa, Xaa, Y and Caa Aaa, Baa, n, and m are as defined herein. In some embodiments, the group of formula (III) is a group of formula (III-A) D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 – Y – Caa wherein D is the antimicrobial moiety; X is absent or is O2Oc; Aaa1 is Val or Leu; Aaa2 is Val or Pro; Aaa3 is absent or is Arg; Yaa is Ala-Pro or Pro; Xaa is Ser or Ala; Baa1 is Gln or Val; Baa2 is Ala or Phe; Baa3 is Asn or Ser; Y is absent or is O2Oc and Caa is Cys or Lys. In some embodiments, the group of formula (III-A) is a group of formula (III-A1) D – X – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – Y – Cys In some embodiments, the group of formula (III-A) is a group of formula (III-A2) D – O2Oc – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – O2Oc – Cys. In some embodiments, the group of formula (III-A) is a group of formula (III-A3) D – X – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – Y – Cys In some embodiments, the group of formula (III-A) is a group of formula (III-A4) D – O2Oc – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – O2Oc – Cys. In some embodiments of any of the above structures, the C terminal amino acid is amidated. For example, in some embodiments, the group of formula (III-A1) is D – X – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – Y – Cys-NH2 In some embodiments, the group of formula (III-A2) is D – O2Oc – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – O2Oc – Cys-NH2. In some embodiments, the group of formula (III-A3) is D – X – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – Y – Cys-NH2 In some embodiments, the group of formula (III-A4) is D–O2Oc–Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – O2Oc – Cys-NH2. In some embodiments of any of the above compounds, D is an antimicrobial peptide. D may be any of the antimicrobial peptides disclosed herein. In some embodiments, D is an N-acylated tridecapeptide or N-acylated tridecalipopeptide (e.g. TriA1, TriB1, TriM1 and derivatives thereof). In some embodiments, D is Oct-TriA1 In some embodiments, the antimicrobial agent thus comprises a polypeptide of formula PRN2028 or PRN2029: Conjugation In the antimicrobial agent of the invention, the microbe-targeting moiety is conjugated to the antimicrobial moiety by the cleavable linker as discussed above. As discussed above, the cleavable linker typically comprises a terminal natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on said microbe-targeting moiety, for example a group Caa as described above. The terminal group may for example be a cysteine or a lysine residue. The attachment between the linker and the microbe-targeting moiety is not limited and any suitable attachment chemistry can be used. Many suitable reactive groups and their chemical targets are known in the art. Some exemplary reactive groups and their corresponding targets include aryl azides which may react with amine, carbodiimides which may react with amines and carboxyl groups, hydrazides which may react with carbohydrates, hydroxmethyl phosphines which may react with amines, imidoesters which may react with amines, isocyanates which may react with hydroxyl groups, carbonyls which may react with hydrazines, maleimides which may react with sulfhydryl groups, NHS-esters which may react with amines, PFP-esters which may react with amines, psoralens which may react with thymine, pyridyl disulfides which may react with sulfhydryl groups, vinyl sulfones which may react with sulfhydryl amines and hydroxyl groups, vinylsulfonamides, and the like. Other suitable chemistry for conjugating the polypeptide to the polynucleotide includes click chemistry. Many suitable click chemistry reagents are known in the art. Suitable examples of click chemistry include, but are not limited to, the following: (a) copper(I)-catalyzed azide-alkyne cycloadditions (azide alkyne Huisgen cycloadditions); (b) strain-promoted azide-alkyne cycloadditions; including alkene and azide [3+2] cycloadditions; alkene and tetrazine inverse-demand Diels-Alder reactions; and alkene and tetrazole photoclick reactions; (c) copper-free variant of the 1,3 dipolar cycloaddition reaction, where an azide reacts with an alkyne under strain, for example in a cyclooctane ring such as in bicycle[6.1.0]nonyne (BCN); (d) the reaction of an oxygen nucleophile on one linker with an epoxide or aziridine reactive moiety on the other; and (e) the Staudinger ligation, where the alkyne moiety can be replaced by an aryl phosphine, resulting in a specific reaction with the azide to give an amide bond. The antimicrobial moiety can be conjugated to the microbe-targeting moiety via a linker (e.g. a peptide linker) wherein the C-terminus of the linker is attached to the antimicrobial moiety and the N terminus of the linker is attached to the microbe-targeting moiety. More often, the N-terminus of the linker is attached to the antimicrobial moiety and the C terminus of the linker is attached to the microbe-targeting moiety. The linker may comprise a naturally occurring reactive functional group which can be used to facilitate conjugation to the microbe-targeting moiety. For example, a cysteine residue can be used to form a disulphide bond to a cysteine residue on the microbe- targeting moiety. A cysteine residue can be used to react with a mameimide group. For instance, as described in the examples, a microbe-targeting moiety such as an antibody as described herein can conjugated to a linker-antimicrobial moiety construct having a C- terminal cysteine residue using MBS (m-maleimidobenzoyl-N-hydroxysuccinimide ester). MBS is an amine-to-sulfhydryl crosslinker and thus can attach the cysteine residue of the construct to a lysine residue of the microbe-targeting moiety. Other cysteine/lysine reactive groups can be used. In some embodiments, the antimicrobial agent provided herein thus comprises a microbe-targeting moiety conjugated to a construct comprising a linker selectively cleavable by said microbe; and an antimicrobial moiety. In some embodiments the antimicrobial agent comprises at least 1, at least 2, at least 3, at least 5, at least 6, at least 7, or at least 8 such constructs. In some embodiments the antimicrobial agent comprises between 1 and 20 of such constructs, for example between 5 and 10 of such constructs. Without being bound by theory, antimicrobial agents which comprise higher numbers of constructs may have higher antimicrobial activity than antimicrobial agents which comprise lower numbers of constructs. Antimicrobial agents which comprise lower numbers of constructs may be easier to generate and/or allow the use of smaller microbe- targeting moieties. Specific embodiments In a specific embodiment, the invention provides: an antimicrobial agent comprising a) a microbe-targeting moiety b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is an antibody; wherein the linker and antimicrobial moiety are comprised in a moiety of form D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 – Y – Caa wherein D is the antimicrobial moiety; X is absent or is O2Oc; Aaa1 is Val or Leu; Aaa2 is Val or Pro; Aaa3 is absent or is Arg; Yaa is Ala-Pro or Pro; Xaa is Ser or Ala; Baa1 is Gln or Val; Baa2 is Ala or Phe; Baa3 is Asn or Ser; Y is absent or is O2Oc and Caa is Cys or Lys; wherein the antimicrobial moiety (D) is Oct-TriA1 or a variant thereof comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker; wherein the linker-antimicrobial moiety is covalently attached to the microbe- targeting moiety by a covalent attachment between Caa and the microbe-targeting moiety. In one embodiment the linker and microbial moiety are of the form: D – O2Oc – Val – Val – Yaa – Pro – Xaa – Pro – Gln – Ala – Asn – O2Oc – Cys-NH2 Yaa is Ala-Pro and Xaa is Ser; and/or D is Oct-Tri-A1; and/or Cys is crosslinked to a Lys residue of said microbe-targeting moiety. In one embodiment the linker and microbial moiety are of the form: D–O2Oc – Leu – Pro – Arg – Yaa – Pro – Xaa – Pro – Val – Phe – Ser – O2Oc – Cys-NH2 Yaa is Pro; Xaa is Ala; and/or D is Oct-Tri-A1; and/or Cys is crosslinked to a Lys residue of said microbe-targeting moiety. Polynucleotides, vectors and host cells The invention also provides one or more isolated polynucleotides (e.g. DNA) encoding an antibody described herein. In one embodiment, the polynucleotide sequence is collectively present on more than one polynucleotide, but collectively together they are able to encode an antibody described herein. For example, the polynucleotides may encode the heavy and/or light chain variable regions(s) of an antibody described herein. The polynucleotides may encode the full heavy and/or light chain of an antibody described herein. Typically, one polynucleotide would encode each of the heavy and light chains. Polynucleotides which encode an antibody described herein can be obtained by methods well known to those skilled in the art. For example, DNA sequences coding for part or all of the antibody heavy and light chains may be synthesised as desired from the corresponding amino acid sequences. General methods by which the vectors may be constructed, transfection methods and culture methods are well known to those skilled in the art. In this respect, reference is made to “Current Protocols in Molecular Biology”, 1999, F. M. Ausubel (ed), Wiley Interscience, New York and the Maniatis Manual produced by Cold Spring Harbor Publishing. A polynucleotide described herein may be provided in the form of an expression cassette, which includes control sequences operably linked to the inserted sequence, thus allowing for expression of the antibody of the invention in vivo. Hence, the invention also provides one or more expression cassettes encoding the one or more polynucleotides that encoding an antibody described herein. These expression cassettes, in turn, are typically provided within vectors (e.g. plasmids or recombinant viral vectors). Hence, in one embodiment, the invention provides a vector encoding an antibody described herein. In another embodiment, the invention provides vectors which collectively encode an antibody described herein. The vectors may be cloning vectors or expression vectors. A suitable vector may be any vector which is capable of carrying a sufficient amount of genetic information, and allowing expression of a polypeptide described herein. The polynucleotides, expression cassettes or vectors described herein are introduced into a host cell, e.g. by transfection. Hence, the invention also provides a host cell comprising the one or more polynucleotides, expression cassettes or vectors of the invention. The polynucleotides, expression cassettes or vectors of the invention may be introduced transiently or permanently into the host cell, allowing expression of an antibody from the one or more polynucleotides, expression cassettes or vectors. Such host cells include transient, or preferably stable higher eukaryotic cell lines, such as mammalian cells or insect cells, lower eukaryotic cells, such as yeast, or prokaryotic cells, such as bacteria cells. Particular examples of cells include mammalian HEK293, such as HEK293F, HEK293T, HEK293S or HEK Expi293F, CHO, HeLa, NS0 and COS cells, or any other cell line used herein, such as the ones used in the Examples. Preferably the cell line selected will be one which is not only stable, but also allows for mature glycosylation. The invention also provides a method for the production of an antibody described herein, comprising culturing a host cell containing one or more vectors of the invention under conditions suitable for the expression of the antibody from the one or more polynucleotides of the invention, and isolating the antibody from said culture. After isolating and purifying the antibodies from the cell culture using well known techniques in the art, they are conjugated with a linker described herein. Hence, the invention also provides a method for the production of an antimicrobial agent of the invention, comprising conjugated an antibody to a linker described herein. Therapeutic Efficacy The antibodies and antimicrobial agents of the present invention are therapeutically useful. References in the following section to an “agent” apply independently to the antimicrobial agent described herein and also to the antibody provided herein, unless implied otherwise by the context. Thus, a reference to the use of an agent described herein in the treatment of prevention of bacterial infection in a subject refers to both the use of an antibody as described herein in the treatment of prevention of bacterial infection in a subject and to the use of an antimicrobial agent as described herein in the treatment of prevention of bacterial infection in a subject. Similarly, references to a composition comprising an agent as described herein refer to compositions comprising an antimicrobial agent as described herein and to compositions comprising an antibody as described herein. Accordingly, provided herein is an agent as described herein, for use in medicine. Also provided herein is an agent as described herein, for use in treating the human or animal body. For the avoidance of doubt, the agent may be administered in the form of a solvate. Also provided is a pharmaceutical composition comprising an agent as described herein together with a pharmaceutically acceptable excipient, carrier or diluent. Typically, the composition contains up to 85 wt% of an antimicrobial agent of the invention. More typically, it contains up to 50 wt% of an agent of the invention. Preferred pharmaceutical compositions are sterile and pyrogen free. Further, when the pharmaceutical compositions provided by the invention contain an agent of the invention which is optically active, the compound of the invention is typically a substantially pure optical isomer. The invention also provides a pharmaceutical composition comprising an antibody of the invention. The composition may comprise a combination (such as two, three or four) of the antibodies of the invention. The pharmaceutical composition may also comprise a pharmaceutically acceptable carrier. The invention further relates to the use of the antibodies the combinations of the antibodies and the pharmaceutical compositions, described herein, e.g. in a method for treatment of the human or animal body by therapy, or in a diagnostic method. The composition of the invention may include one or more pharmaceutically acceptable salts. A "pharmaceutically acceptable salt" refers to a salt that retains the desired biological activity of the parent compound and does not impart any undesired toxicological effects. Examples of such salts include acid addition salts and base addition salts. As used herein, a pharmaceutically acceptable salt is a salt with a pharmaceutically acceptable acid or base. Pharmaceutically acceptable acids include both inorganic acids such as hydrochloric, sulphuric, phosphoric, diphosphoric, hydrobromic or nitric acid and organic acids such as oxalic, citric, fumaric, maleic, malic, ascorbic, succinic, tartaric, benzoic, acetic, methanesulphonic, ethanesulphonic, benzenesulphonic or p- toluenesulphonic acid. Pharmaceutically acceptable bases include alkali metal (e.g. sodium or potassium) and alkali earth metal (e.g. calcium or magnesium) hydroxides and organic bases such as alkyl amines, aralkyl amines and heterocyclic amines. Hydrochloride salts and acetate salts are preferred, in particular hydrochloride salts. The composition may be provided as a kit comprising instructions to enable the kit to be used in the methods and medical uses described herein or details regarding which subjects the method may be used for. As explained above, the agents provided herein are particularly useful in treating or preventing bacterial infection. In particular, they are active against Gram-negative bacteria. This is discussed in more detail below. However the antimicrobial agents provided herein are in some cases useful against Gram-positive bacterial such as Streptococcus pneumoniae. The agents provided herein may be used as standalone therapeutic agents. For example, they are particularly useful in standalone regimes for treating pathological conditions associated with bacterial infection, as described in more detail herein. The agents provided herein may be used as standalone adjuncts in antibacterial therapy, for example in chemotherapy regimes. Alternatively, they may be used in combination with one or more other antibiotic agents. A pharmaceutical composition provided herein may comprise one or more other antibiotic agents. The one or more other antibiotic agents administered with the agent provided herein or comprised in a composition provided herein may be selected from β-lactam antibiotics such as carbapenems, penicillins, cephalosporins and penems. Examples of carbapenem antibiotics include Imipenem, Meropenem, Ertapenem, Doripenem and Biapenem. Examples of penicillins include Amoxicillin, Ampicillin, Ticarcillin, Piperacillin and Cloxacillin. Examples of cephalosporins include Cefazolin, Ceftriaxone, Ceftazidine and Ceftobiprole. Examples of penems include Faropenem. The other antibiotic agent may be selected from tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides. Examples tetracyclines include demeclocycline, doxycycline, eravacycline, minocycline, omadacycline, sarecycline and tetracycline. Examples of quinolones include ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin and gemifloxacin. Examples of lincomycins include clindamycin and lincomycin. Examples of macrolides include azithromycin, clarithromycin, erythromycin, and fidaxomicin. Examples of sulphonamides include sulfamethoxazole, trimethoprim and sulfasalazine. Examples of glycopeptides include dalbavancin, oritavancin, telavancin and vancomycin. Examples of aminoglycosides include gentamicin, tobramycin and amikacin. The agents provided herein may find particular use in treating or preventing bacterial infection caused by bacteria which are resistant to treatment with antibiotic agents when administered alone. In particular, the agents provided herein may be useful in treating or preventing bacterial infection caused by drug (e.g. antibiotic) resistant bacteria, particularly where the resistance is caused by the expression (e.g. upregulated expression) of multi-drug efflux pumps. The resistance may be caused by expression (e.g. upregulated expression) of tripartite multidrug efflux pumps of family HAE-RND (hydrophobic and ampiphilic efflux resustance-nodulation cell division family). One example of such multi- drug resistance pumps is MtrE. Accordingly, the agents provided herein may be used in the treatment or prevention of bacterial infection caused by bacteria which express MtrE or a paralog or homolog thereof. This is particularly useful as treatment of prevention of such infections with conventional antibiotic agents is often unsuccessful. As noted, the agents of the invention are useful in treating or preventing bacterial infection. The invention therefore provides an agent for use in medicine. The invention also provides the use of an agent of the invention in the manufacture of a medicament. The invention also provides compositions comprising the agents of the invention, as described here. Such compositions are also useful in treating or preventing bacterial infection. The present invention therefore provides a composition as defined herein for use in medicine. The invention also provides the use of a composition of the invention in the manufacture of a medicament. As explained above, the agents and compositions provided herein the invention are useful in treating or preventing bacterial infection. The invention therefore also provides a method of treating or preventing bacterial infection in a subject, which method comprises administering to said subject an effective amount of an agent or composition as described herein. Further provided is use of an agent or composition as described herein for the manufacture of a medicament for use in treating or preventing bacterial infection. As further explained above, the agents of the invention are useful in combination with a further antibacterial compound. The invention therefore provides an agent of the invention for use in treating or preventing bacterial infection, wherein such use comprises co-administering the agent of the invention with a further antibacterial compound. The invention also provides the use of an agent of the invention in the manufacture of a medicament for treating or preventing bacterial infection by co-administration of the agent with a further antibacterial compound. The invention also provides a method for treating or preventing bacterial infection by co-administering the agent of the invention and a further antibacterial compound to a subject in need thereof. The further antibacterial compound is preferably an antibacterial compound as described herein. In one aspect, the subject to be treated is a mammal, in particular a human. However, it may be non-human. Preferred non-human animals include, but are not limited to, primates, such as marmosets or monkeys, commercially farmed animals, such as horses, cows, sheep or pigs, and pets, such as dogs, cats, mice, rats, guinea pigs, ferrets, gerbils or hamsters. The subject can be any animal that is capable of being infected by a bacterium as described in more detail herein. The agents and compositions described herein are useful in the treatment of bacterial infection which occurs after a relapse following an antibiotic treatment. The compounds, compositions and combinations can therefore be used in the treatment of a patient who has previously received antibiotic treatment for the (same episode of) bacterial infection. In one embodiment the bacterium causing the infection may be any pathogenic bacterium which expresses a protease capable of cleaving the linker of the antimicrobial agent. Preferably the bacterium causing the infection expresses a serine protease. Typically the bacterium expresses an IgA specific serine protease. The protease expressed by the bacterium may be of E.C. class 3.4.21. The protease may be of EC class 3.4.24. Preferably the protease expressed by the bacterium is of E.C. class 3.4.21.72 or 3.4.24.13, most preferably of 3.4.21.72. In other embodiments the protease may be of EC class 3.4.22. The protease may be at least 70% identical to the amino acid sequence of any one of SEQ ID NOs: 31-35. Often the protease is at least 70% identical to the amino acid sequence of SEQ ID NO: 31-34, preferably 31-32. The bacterium is typically Gram-negative. The bacterium may in particular be a pathogenic bacterium. The bacterium may be an opportunistic pathogen. Typically, the bacterial infection to be treated using the compounds of the invention is resistant to treatment with a conventional antibiotic when the conventional antibiotic is used alone. The bacterium may be a drug-resistant bacterium. The bacterium may be a multi-drug resistant bacterium. The bacterium may be resistant to one or more antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and/or aminoglycosides. Exemplary compounds in these classes are described in more detail herein. The bacterial infection may be caused by bacteria from the families Neisseriaceae, Streptococcaceae, Pasteurellaceae and/or Pseudomonadaceae. The bacterial infection is often caused by bacteria from the families Neisseriaceae, Streptococcaceae, and/or Pasteurellaceae. More often the bacterial infection is caused by bacteria from the family Neisseriaceae. The bacterial infection may be caused Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, Haemophilus influenza or Pseudomonas aeruginosa. More typically the bacterial infection is caused by Neisseriaceae gonorrhoeae, Neisseria meningitides, Streptococcus pneumoniae, or Haemophilus influenza. Still more typically the bacterial infection is caused by Neisseriaceae gonorrhoeae or Neisseria meningitides, preferably Neisseriaceae gonorrhoeae. For example, the bacterial infection may be caused by Neisseriaceae gonorrhoeae strain FA1090. The agent or composition of the invention may be used to treat or prevent infections and conditions caused by any one or a combination of the above-mentioned bacteria. The agent or composition of the invention may be used in the treatment or prevention of any suitable pathological condition caused by a microbial infection, upper and / or lower respiratory tract infections, skin and soft tissue infections and / or urinary tract infections. The agent or composition of the invention may be used in the treatment or prevention of gonorrhoea, disseminated gonococcemia, septic arthritis, gonococcal ophthalmia neonatorum, pelvic inflammatory disease, ectopic pregnancy, pelvic scarring (including infertility arising from pelvic scarring), pharyngitis, proctitis, and HIV. Such conditions may be particularly amenable to treatment when the microbial infection is caused by Neisseriaceae gonorrhoeae. The agent or composition of the invention may be used in the treatment or prevention of meningitis, meningococcemia and septicaemia. Such conditions may be particularly amenable to treatment when the microbial infection is caused by Neisseria meningitides. The agent or composition of the invention may be used in the treatment or prevention of pneumonia, meningitis, sepsis, otitis media, pericarditis, epiglottitis, septic arthritis, cellulitis, and osteromyelitis. Such conditions may be particularly amenable to treatment when the microbial infection is caused by Haemophilus influenza. The agent or composition of the invention may be used in the treatment or prevention of pneumonia and sepsis. Such conditions may be particularly amenable to treatment when the microbial infection is caused by Streptococcus pneumoniae. The agent or composition of the invention may be used in the treatment or prevention of pneumonia (e.g. diffuse bronchopneumonia), septic shock (e.g. associated with ecthyma gangrenosum), urinary tract infection, gastrointestinal infection, necrotising enterocolitis, and skin and soft tissue infections (e.g. hemorrhage and necrosis). Such conditions may be particularly amenable to treatment when the microbial infection is caused by Pseudomonas aeruginosa. An agent or composition of the invention can be administered to a subject in need thereof in order to prevent the onset or reoccurrence of one or more symptoms of the bacterial infection. This is prophylaxis. In this embodiment, the subject can be asymptomatic. The subject is typically one that has been exposed to the bacterium. A prophylactically effective amount of the agent or formulation is administered to such a subject. A prophylactically effective amount is an amount which prevents the onset of one or more symptoms of the bacterial infection. An agent or composition provided herein can be administered to the subject in order to treat one or more symptoms of the bacterial infection. In this embodiment, the subject is typically symptomatic. A therapeutically effective amount of the agent or composition is administered to such a subject. A therapeutically effective amount is an amount effective to ameliorate one or more symptoms of the disorder. The agent or composition provided herein may be administered in a variety of dosage forms. Thus, it can be administered orally, for example as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules. Compositions may also be administered parenterally, whether subcutaneously, intravenously, intramuscularly, intrasternally, transdermally or by infusion techniques. The agent or composition may also be administered as a suppository. Preferably, the agent or composition may be administered via inhaled (aerosolised) or intravenous administration, most preferably by inhaled (aerosolised) administration. Therapeutic compositions typically must be sterile and stable under the conditions of manufacture and storage. The composition can be formulated as a solution, microemulsion, liposome, or other ordered structure suitable to high drug concentration. The agent or composition is typically formulated for administration with a pharmaceutically acceptable carrier or diluent. Examples of suitable aqueous carriers include water, buffered water and saline. Other suitable pharmaceutically acceptable carriers include ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. In many cases, it will be desirable to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, or sodium chloride in the composition. For example, solid oral forms may contain, together with the active compound(s), diluents, e.g. lactose, dextrose, saccharose, cellulose, corn starch or potato starch; lubricants, e.g. silica, talc, stearic acid, magnesium or calcium stearate, and/or polyethylene glycols; binding agents; e.g. starches, arabic gums, gelatin, methylcellulose, carboxymethylcellulose or polyvinyl pyrrolidone; disaggregating agents, e.g. starch, alginic acid, alginates or sodium starch glycolate; effervescing mixtures; dyestuffs; sweeteners; wetting agents, such as lecithin, polysorbates, laurylsulphates; and, in general, non toxic and pharmacologically inactive substances used in pharmaceutical formulations. Such pharmaceutical preparations may be manufactured in known manner, for example, by means of mixing, granulating, tableting, sugar coating, or film coating processes. The agent or composition may be formulated for inhaled (aerosolised) administration as a solution or suspension. The agent or composition may be administered by a metered dose inhaler (MDI) or a nebulizer such as an electronic or jet nebulizer. Alternatively, the agent or composition may be formulated for inhaled administration as a powdered drug, such formulations may be administered from a dry powder inhaler (DPI). When formulated for inhaled administration, the agent or composition may be delivered in the form of particles which have a mass median aerodynamic diameter (MMAD) of from 1 to 100 µm, preferably from 1 to 50 µm, more preferably from 1 to 20 µm such as from 3 to 10 µm, e.g. from 4 to 6 µm. When the agent or composition is delivered as a nebulized aerosol, the reference to particle diameters defines the MMAD of the droplets of the aerosol. The MMAD can be measured by any suitable technique such as laser diffraction. Liquid dispersions for oral administration may be syrups, emulsions and suspensions. The syrups may contain as carriers, for example, saccharose or saccharose with glycerine and/or mannitol and/or sorbitol. Suspensions and emulsions may contain as carrier, for example a natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol. The suspension or solutions for intramuscular injections or inhalation may contain, together with the active compound, a pharmaceutically acceptable carrier, e.g. sterile water, olive oil, ethyl oleate, glycols, e.g. propylene glycol, and if desired, a suitable amount of lidocaine hydrochloride. Solutions for inhalation, injection or infusion may contain as carrier, for example, sterile water or preferably they may be in the form of sterile, aqueous, isotonic saline solutions. Pharmaceutical compositions suitable for delivery by needleless injection, for example, transdermally, may also be used. A therapeutically or prophylactically effective amount of the agent or composition may be administered to a subject. The dose may be determined according to various parameters, especially according to the compound used; the age, weight and condition of the subject to be treated; the route of administration; and the required regimen. Again, a physician will be able to determine the required route of administration and dosage for any particular subject. A typical daily dose is from about 0.01 to 100 mg per kg, preferably from about 0.1 mg/kg to 50 mg/kg, e.g. from about 1 to 10 mg/kg of body weight, according to the activity of the specific inhibitor, the age, weight and conditions of the subject to be treated, the type and severity of the disease and the frequency and route of administration. Preferably, daily dosage levels are from 5 mg to 2 g. When the agent or composition is administered to a subject in combination with another active agent (for example together with a further antibiotic agent), the dose of the other active agent can be determined as described above. The dose may be determined according to various parameters, especially according to the agent used; the age, weight and condition of the subject to be treated; the route of administration; and the required regimen. Again, a physician will be able to determine the required route of administration and dosage for any particular subject. A typical daily dose is from about 0.01 to 100 mg per kg, preferably from about 0.1 mg/kg to 50 mg/kg, e.g. from about 1 to 10 mg/kg of body weight, according to the activity of the specific inhibitor, the age, weight and conditions of the subject to be treated, the type and severity of the disease and the frequency and route of administration. Preferably, daily dosage levels are from 5 mg to 2 g. The antibacterial properties of the compounds described herein mean that they are also useful in the treatment of bacterial infection in vitro, i.e. other than by the treatment of human or animal subjects. Thus, the invention also provides a cleaning composition comprising an agent as described herein. The cleaning composition may further comprise, for example, a detergent, a surfactant (including ionic and non-ionic surfactants), a diluent, a bleach (including a hypochlorite such as sodium hypochlorite or calcium hypochlorite, chlorine, chlorine dioxide, hydrogen peroxide or an adduct thereof, sodium perborate, and sodium percarbonate), an alcohol (such as ethanol or isopropanol), or a disinfectant. Typically, the disinfectant may be selected from benzyl-4-chlorophenol, amylphenol, phenylphenol, glutaraldehyde, alkyl dimethyl benzyl ammonium chloride, alkyl dimethyl ethylbenzyl ammonium chloride, iodine, peracetic acid and chlorine dioxide. Typically, the detergent may be an alkaline detergent such as sodium hydroxide, sodium metasilicate, or sodium carbonate, or an acid detergent such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, citric acid, or tartaric acid. Further embodiments of the invention Also provided herein are kits comprising antibodies or other compositions of the invention and instructions for use. The kit may further contain one or more additional reagents, such as an additional therapeutic or prophylactic agent as discussed herein. The kit may comprise an antimicrobial agent as described herein together with instructions for use. Also provided herein is a method of making an antimicrobial agent as described herein, comprising conjugating an antimicrobial moiety to a microbe-targeting moiety via a linker, wherein said linker is selectively cleavable by said microbe. Typically the antimicrobial moiety, microbe-targeting moiety and linker are as described herein. Also provided is a protease-cleavable oligopeptide comprising a group of formula (Aaa)n – [PRS] – (Baa)m – Y – Caa wherein - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on a microbe-targeting moiety such as an antibody; and - [PRS], (Aaa), (Baa), n, m and Y are as defined in herein in more detail.. Further provided is the use of a protease-cleavable oligopeptide as described herein to conjugate a microbe-targeting moiety to an antimicrobial moiety. Typically, said microbe-targeting moiety and said antimicrobial moiety are as defined herein. It is a benefit of the present invention that the protease-cleavable oligopeptides described herein are capable of being cleaved even when conjugated to a microbe-targeting moiety and/or a antimicrobial moiety as described herein. The invention also relates to identifying subjects that have a bacterial infection, such as infection by N.gonorrhoeae. For example, the methods and uses of the invention may involve identifying the presence of a bacteria (e.g. N.gonorrhoeae) in a sample. The detection may be carried out in vitro or in vivo. In certain embodiments, the invention relates to population screening. In some embodiments said methods and uses comprise contacting the sample with an agent as described herein and determining the extent of bacterial cell killing by the agent, wherein the extent of selective cell killing can be correlated with the concentration of the bacteria (e.g. N.gonorrhoeae) in the sample. The invention relates to analysing samples from subjects. The sample may be tissues, cells and biological fluids isolated from a subject, as well as tissues, cells and fluids present within a subject. The sample may be blood and a fraction or component of blood including blood serum, blood plasma, or lymph. Typically, the sample is from a throat swab, nasal swab, or saliva. In some embodiments the sample to be analysed is contacted with an agents as described herein. Other It is to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to be limiting. In addition as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the content clearly dictates otherwise. Thus, for example, reference to “a linker” includes two or more linkers. Furthermore, when referring to “≥x” herein, this means equal to or greater than x. The term “comprising” encompasses “including” as well as “consisting” e.g. a composition “comprising” X may consist exclusively of X or may include something additional e.g. X + Y. For the purpose of this invention, in order to determine the percent identity of two sequences (such as two polynucleotide or two polypeptide sequences), the sequences are aligned for optimal comparison purposes (e.g. gaps can be introduced in a first sequence for optimal alignment with a second sequence). The nucleotide or amino acid residues at each position are then compared. When a position in the first sequence is occupied by the same nucleotide or amino acid as the corresponding position in the second sequence, then the nucleotides or amino acids are identical at that position. The percent identity between the two sequences is a function of the number of identical positions shared by the sequences (i.e. % identity = number of identical positions /total number of positions in the reference sequence × 100). Typically the sequence comparison is carried out over the length of the reference sequence. For example, if the user wished to determine whether a given (“test”) sequence is 95% identical to SEQ ID NO: 3, SEQ ID NO: 3 would be the reference sequence. To assess whether a sequence is at least 95% identical to SEQ ID NO: 3 (an example of a reference sequence), the skilled person would carry out an alignment over the length of SEQ ID NO: 3, and identify how many positions in the test sequence were identical to those of SEQ ID NO: 3. If at least 95% of the positions are identical, the test sequence is at least 95% identical to SEQ ID NO: 3. If the sequence is shorter than SEQ ID NO: 3, the gaps or missing positions should be considered to be non-identical positions. The skilled person is aware of different computer programs that are available to determine the homology or identity between two sequences. For instance, a comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm. In an embodiment, the percent identity between two amino acid or nucleic acid sequences is determined using the Needleman and Wunsch (1970) algorithm which has been incorporated into the GAP program in the Accelrys GCG software package (available at http://www.accelrys.com/products/gcg/), using either a Blosum 62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6. As used herein, a C4-12 alkyl group is a linear or branched alkyl group containing from 4 to 12 carbon atoms. A C4-12 alkyl group is often a C6-10 alkyl group such as a C8-10 alkyl group. A C1-2 alkyl group may be for example methyl or ethyl, typically methyl. For the avoidance of doubt, where two alkyl groups are present, the alkyl groups may be the same or different. As used herein, a C4-12 alkenyl group is a linear or branched group containing from 4 to 12 carbon atoms and having one or more, e.g. one or two, typically one double bonds. A C4-12 alkenyl group is often a C6-10 alkenyl group such as a C8-10 alkenyl group. For the avoidance of doubt, where two alkenyl groups are present, the alkenyl groups may be the same or different. As used herein, a C4-12 alkynyl group is a linear or branched group containing from 4 to 12 carbon atoms and having one or more, e.g. one or two, typically one triple bonds. A C4-12 alkynyl group is often a C6-10 alkynyl group such as a C8-10 alkynyl group. For the avoidance of doubt, where two alkynyl groups are present, the alkynyl groups may be the same or different. When the agent described herein comprises a peptide (e.g. a peptide-based linker and/or a peptide-based antimicrobial moiety, the peptide can be synthesized by standard methods such as solid-phase peptide synthesis, known to those of skill in the art and commercially available from providers such as ISCA Biochemicals (Exeter, UK). Agents described herein are typically used in enantiomerically or diastereoisomerically pure form, or in the form of a mixture of isomers. Further, for the avoidance of doubt, the agents of the invention may be used in any tautomeric form. Typically, the agent or substance described herein contains at least 50%, preferably at least 60, 75%, 90% or 95% of a compound according to Formula (I) which is enantiomerically or diasteriomerically pure. Typically, an agent or substance described herein comprises by weight at least 60%, such as at least 75%, 90%, or 95% of a single enantiomer or diastereomer. Preferably, the agent or substance described herein is substantially optically pure. All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety. The following examples illustrate the invention. They do not, however, limit the invention in any way. In this regard, it is important to understand that the particular assays used in the Examples section are designed only to provide an indication of biological activity. There are many assays available to determine biological activity, and a negative result in any one particular assay is therefore not determinative. Examples This example investigated the antimicrobial activity of a newly designed antibody- peptide conjugate that specifically targets N. gonorrhoeae. Results Monoclonal antibodies (mAbs) against MtrE were generated and isolated. Three antibodies mAb184a-D10, mAb97A-D6, and mAb135a-D6 were identified to exhibit high specificity for MtrE. The sequence information of these antibodies are provided in Table 4 and further characterisation data are provided in Figure 10. All three antibodies (mAb184a-D10, mAb97A-D6, and mAb135a-D6) specifically bind to MtrE in N. gonorrhoeae (Figures 11 to 13). Notably, mAb97A-D6 and mAb135a-D6 cross react with MtrE in N. meningitis, whereas mAb184a-D10 does not (Figure 12). The specific binding of the mAb to two gonococcal strains, FA1090 and MS11, were confirmed by flow cytometry. Gonococcal mutants lacking MtrE (ΔmtrE) were included as negative controls. Results show that mAb184a-D10 specifically recognized MtrE on the bacterial surface (Figure 1A). Detection of MtrE by the mAbs of a range of clinical isolates was also examined by Western blot analysis (Figure 1B). The mAbs identified a band of the predicted molecular mass of MtrE expressed by over 50 gonococcal clinical isolates. Peptides were synthesised to conjugate to the mAbs, resulting in antibody-peptide conjugates (APCs): mAb 184a-D10:PRN2028, mAb 184a-D10:PRN2029 and mAb 184a- D10:PRN2208. The peptide sequences are show in Table 1, and the strategy and structure of the APCs are shown in Figures 2A and 2B. Each of PRN2028 and PRN2029 comprises the sequence of the antimicrobial peptide, Oct-TriA1, together with a linker sequence which is predicted to be cleaved by the gonococcal IgA proteases, and a terminal cysteine for conjugation. Figures 6A and 6B show the IgAP cleavage sites in PRN2028 and PRN029, which would result in the release of antimicrobial peptides corresponding to PRN 1967 and PRN 1968, respectively. PRN 2208 comprises the sequence of the antimicrobial peptide, Oct-TriA1, together with a linker sequence which is not cleaved by the gonococcal IgA proteases, and a terminal cysteine for conjugation. Table 1 MALDI-TOF of the peptides following maleamide-mediated conjugation with lysine side groups on the mAb 184a demonstrated covalent linkage with the peptides. On average around 8 peptides were linked per mAb. Flow cytometry confirmed that the presence of the peptides did not inhibit mab binding to MtrE on the gonococcal surface (Figure 2C). It was then confirmed that the linker sequence can be cleaved by the IgA protease secreted by the gonococcus. Initially, it was demonstrated that culture supernatants of gonococcus can cleave hIgA1 (Figure 3A). Furthermore, mass spectrometry confirmed that culture supernatants from wild-type gonococcus, but not from the IgA protease mutant, can cleave and release the antimicrobial peptides PRN1968 and PRN 1969 from the anti-MtrE mAb (Figures 3B, 6C, 6D and 7). Next, kill curves were performed and these demonstrate that the antimicrobial peptide conjugates (APCs) are bactericidal against the gonococcus in an IgA protease dependent manner (Figures 4, 8, 14 and 16). The minimum inhibitory concentration of the APCs and the free peptides against a range of gonococcal strains is shown in Table 2. These confirm the activity of the APCs against a variety of well characterized isolates. Table 2. Comparison of the antimicrobial activity of Oct-TriA1 with different N. †Activities are reported in µg/ ml †Activities are reported in µg/ ml Finally, it was shown that the APCs exhibit significantly less haemolytic activity against human RBCs than the peptides alone, as well as markedly reduced cytotoxicity against HK-2 human renal cells and End1/E6E7 cervical endothelial cells (Figures 5, 9 and 15, Table 3). Table 3 Comparison of human erythrocyte hemolysis (HC50) and cytotoxicity (EC50) against HK-2 cells on exposure to Oct-TriA1 analogues and APCs * * the concentration of peptide or APC that lyses 50% of erythrocytes ◊ half maximal effective concentration In conclusion, the results demonstrate that conjugation of an antimicrobial agent, such as an AMP, impairs its toxicity against human cells, while the targeting of the antimicrobial agent by the targeting moiety, e.g. an antibody, and protease-dependent cleavage, e.g. IgA, targets the APC specifically to the microbe of interest, such as gonococcus. The latter overcomes the major stumbling block in the development of AMPs, namely their inherent toxicity against mammalian cells. Materials and methods Generation of ΔmtrE and ΔigAP strains Genomic DNA from two gonococcal strains, MS11 and FA1090, was isolated. For MtrE (NEIS1632), NEBuilder® assembly tool was used to design primers using pUC19 plasmid as a template per the manufacturer’s instructions. Overlap 1632 primers were designed for insertional inactivation of MtrE with a Kan cassette. Fragments were ligated into pUC19 plasmid digested with BamHI and XbaI. Assembled products were transformed into E. coli DH5α and confirmed by sequencing and restriction digestion. Prior to transformation into N. gonorrhoeae, pUC19:ΔmtrE was digested with AatII and BsaI and transformed as previously described (Dillard, J. P. Genetic Manipulation of Neisseria gonorrhoeae. Curr Protoc Microbiol Chapter 4, Unit4A.2.16 (2011). Deletion of gonococcal IgAP (NEIS0651) was achieved by amplifying the upstream and downstream fragments from MS11 and FA1090 gDNA with a Kan cassette overlap. The construct was assembled from amplified fragments and Kan cassette by overlap PCR. PCR product was gel purified and transformed into N. gonorrhoeae as previously described (Dillard, J. P. Genetic Manipulation of Neisseria gonorrhoeae. Curr Protoc Microbiol Chapter 4, Unit4A.2.16 (2011). Production of recombinant MtrE Genomic DNA was isolated. mtrE was amplified from N. gonorrhoeae FA1090 genomic DNA using primers Fwd1632 (5′- AGCCTTTGCATTGCATATGTGCACCATGATT-3′; SEQ ID NO: 37; Nde I site underlined) and Rev1632 (5′- TTGTTTGCCCGGATCCTTATTTGCCGGTTT-3′; SEQ ID NO: 38; BamHI site underlined). The product was ligated into pET14b, resulting in a construct for expression of MtrE with a N-terminal His tag under an inducible promoter. For MtrE expression, E. coli B834 containing pET14b:mtrE was grown in TB medium and IPTG was added to a final concentration of 1 mM. Bacteria were subsequently grown for 24 h at 22°C and harvested. The lysates were centrifuged, and recombinant MtrE was purified by affinity chromatography using a HisTrap column and eluted with 300 mM imidazole. Further purification was performed by size exclusion chromatography. Protein concentrations were estimated. Generation of MtrE mAbs Female BALB/c mice (6 to 8 weeks old; Charles River, Margate, UK) were immunized with recombinant MtrE (20 μg) adsorbed to aluminum hydroxide [final composition, 0.5 mg/ml Al(OH)3, 10 mM histidine-HCl] by mixing overnight at 4°C on an end to end rocker. Antigens were given by the intraperitoneal route on days 0, 21, and 35. The spleen and sera were harvested on day 49 under terminal anesthesia by cardiac puncture. B lymphocytes were fused to NS0 myeloma cells (Galfrè, G. & Milstein, C. Preparation of monoclonal antibodies: strategies and procedures. Methods Enzymol 73, 3- 46 (1981).) with polyethylene glycol (PEG 1500, Roche, UK) (D.Y., M., J.L., C. & K.A.F., P. in Techniques in immunocytochemistry Vol. 2 (ed Bullock GR and Petrusz Peds) 175- 216 (Academic Press, 1983).). Fused cells were plated in RPMI 1640 containing 2 mM L- glutamine, penicillin (100 U/ml), streptomycin (100 μg/ml), and 1% Ultroser G (Pal France). After 24 hours, 2% hypoxanthine adminopterin thymidine (HAT, Life technologies) was added to the wells. Hybridoma clone supernatants were screened by ELISA against recombinant MtrE prior to positive hybridomas being cloned by limiting dilution and reselected by ELISA (Caesar, J. J. et al. Competition between antagonistic complement factors for a single protein on N. meningitidis rules disease susceptibility. Elife 3 (2014)). Antibodies were sequenced by whole transcriptome shotgun sequencing (RNA- Seq). Hybridomas were cultured in IMDM medium containing 10% FBS and incubated at 37oC in a 5% CO2 environment. Total RNA was extracted from cells and a barcoded cDNA library generated through RT-PCR using a random hexamer. Next Generation Sequencing was performed on an Illumina HiSeq sequencer. Contigs were assembled and data is mined for antibody sequences using a pattern match approach which identifies all viable antibody sequences (i.e. those not containing stop codons). The species and isotype of the identified antibody genes were confirmed and variable heavy and variable light domains were identified separately. Sequences were compared with known aberrant (i.e. non-functional) antibody genes that are present in many hybridomas and these genes were removed from analysis when necessary. mAb screening ELISA ELISA plates were coated with recombinant MtrE (5 µg/ml, 50 µl per well) for three hours at room temperature before blocking overnight with 3% skimmed milk in PBS 0.05% Tween 20. Plates were incubated with neat hybridoma culture supernatant and binding was detected with goat anti-mouse HRP (Dako) followed by ELISA substrate and stop solution. mAb purification and isotyping Murine anti-MtrE mAbs were purified from tissue culture supernatants by protein G affinity chromatography. Briefly, hybridoma tissue culture supernatant was diluted 50:50 with mAb binding buffer (50mM sodium acetate, pH 5.0). Protein G chromatography cartridges (Pierce, ThermoFisher Scientific) were equilibrated with 20 ml of binding buffer prior to applying diluted supernatant manually at a flow rate of 1 ml/ min. After washing with 20 ml of binding buffer (50mM sodium acetate, pH 5.0), column bound-antibody was eluted twice with 10 ml of Pierce IgG Elution Buffer and immediately neutralized with 10% (vol/vol) of neutralization buffer (2 M Tris buffer, pH 8.0). Purified mAbs were then dialysed into BupHTM PBS overnight and quantified using a Nanodrop 2000c spectrophotometer. Murine mAb isotype was confirmed using the mouse monoclonal antibody isotyping kit (Bio-Rad) according to manufacturer’s instructions. SDS-PAGE and Western blot analysis To examine mAb specificity and detect MtrE in clinical N. gonorrhoeae isolates, bacteria were grown on GCB agar overnight and 1 × 109 CFU/ml bacteria were suspended in SDS-PAGE loading buffer (100 mM Tris-HCl, pH 6.8, 20 μM β-mercaptoethanol, 4% SDS, 0.2% bromophenol blue, 20% glycerol) prior to separation of on 14% polyacrylamide gels. Proteins were transferred to Immobilon P polyvinylidene difluoride (PVDF) membrane (Millipore, USA) using the Trans-Blot SD semi-dry transfer system (Bio-Rad, USA). Membranes were blocked in 3% (wt/vol) skimmed milk-PBS with 0.05% (vol/vol) Tween 20 overnight and then incubated with neat hybridoma tissue culture supernatant or purified anti-MtrE mAb (5 μg/ ml) in antibody dilutant (1% (w/v) skimmed milk in PBS). Membranes were washed three times in PBS with 0.05% (vol/vol) Tween 20, and incubated with goat anti-mouse HRP (Dako, UK), and subjected to further washing. Binding was detected using ECL Western blotting detection kit (Amersham, USA). Flow cytometry N. gonorrhoeae was grown on GCB agar overnight and quantified as described above. For detection of mAbs or mAb conjugates binding to gonococcal MtrE, 1 × 108 CFU/ml of bacteria were re-suspended in 100 μl of mAb (5 μg/ ml) for 30 min at room temperature. After three washes in wash buffer (0.05% (w/v) BSA/PBS), binding was detected following incubation for 30 min with goat anti-mouse IgG-Alexa fluor® 647 conjugate (Molecular Probes, Life Technologies) at room temperature. Samples were washed three times in wash buffer and then fixed in 3% paraformaldehyde for 30 minutes at room temperature. Cells were washed three times in wash buffer and resuspended in 200 μl of PBS prior to running on a FACSCalibur (BD Biosciences), with at least 104 events recorded. Results were analysed by calculating the geometric mean fluorescence (FL-4) in FlowJo vX software (Tree Star). Statistical significance was tested using an unpaired Student t test (GraphPad Prism v.6.0). Conjugation of Oct-TriA1 derivatives with mAb m-maleimidobenzoyl-N-hydoxysuccinimide ester (MBS) was dissolved in dimethylformamide (50 mM). MBS (final concentration, 5 mM) was added to the purified mAb (0.1 mM in BupHTM PBS) and incubated at room temperature for 60 minutes. Excess MBS was removed over ZebaTM Spin desalting columns (ThermoFisher scientific) according to manufactures instructions. Briefly, columns were centrifuged at 1500 × g for 1 minute to remove storage solution prior to washing the column with three times with BupHTM PBS . Sample was applied the centre of the compacted resin bed and eluted by centrifugation 1500 × g for 2 minutes. Finally the peptide (1.25 mM) was added in 100- fold molar excess and incubated for at least 2 hours at room temperature. To remove unconjugated peptides, mAb:peptide conjugates were dialysed using slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) into PBS (Oxoid) overnight at 4oC. MALDI-TOF MS analysis of mAb:peptide conjugates Matrix-Assisted Laser Desorption Ionization time of flight mass spectrometry (MALDI-TOF-MS) was conducted using a Bruker Microflex LRF MALDI TOF mass spectrometer, equipped with a 60Hz nitrogen laser at 337nm. Super DHB (mixture of 2,5- dihydroxybenzoic acid (2,5-DHB) and 2-hydroxy-5-methoxybenzoic acid) was used as a matrix. Cleavage of hIgA1 by gonococcal IgAP N. gonorrhoeae strains were assessed for IgA1 protease activity by incubation with purified hIgA1 (abcam, UK). hIgA1 (5 µg) or PBS as a control, was incubated with the supernatant (20 μl) from a 24 h culture of N. gonorrhoeae grown GW for 4 h at 37 °C. Cleavage was assessed by SDS-PAGE stained with Coomassie blue or after transfer to PDVF and probed with anti-hIgA-HRP. Cleavage and detection of Oct-TriA1 derivatives and mAb:peptide conjugates To assay cleavage of peptides and mAb:peptide conjugates with an IgAP cleavable linker, supernatant from N. gonorrhoeae strains were harvested after growth for 24 h in FB medium. Supernatant was then dialysed overnight into PBS using a slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) to remove low molecular weight proteins and retain IgAP. Peptides (350 μg) or mAb:peptide conjugates were incubated for 4 h at 37 °C into dialysed supernatant (100 μl). Samples were subsequently desalted using Pierce™ Peptide Desalting Spin Columns (Thermo Scientific) according to manufactures instructions. Briefly, centrifuge desalting columns at 5,000 × g for 1 minute to remove packing solution. Wash the spin column twice with acetonitrile, and twice with 0.1% trifluoroacetic acid. Load sample and centrifuge at 3,000 × g for 1 minute prior to washing with 0.1% trifluoroacetic acid. Samples were eluted twice with 300 μl 50% acetonitrile, 0.1% trifluoroacetic acid. Cleavage of peptides was then analysed by mass spectrometry with mass spectra recorded on a Waters Micromass LCT premier orthogonal acceleration time-of-flight (oa-TOF) Mass spectrometer using electrospray ionization (ESI- MS). Determination of MICs by broth microdilution Microdilution plates were prepared using serial twofold dilutions of antimicrobials in FB as described previously. Briefly, To prepare the inoculum, N. gonorrhoeae strains were resuspended in PBS from cultures grown on GCB agar plates for 16–18 h at 37 °C, 5 % CO2. Bacterial suspensions in PBS were adjusted to ODA600 nm of 1.0 (equivalent to approximately 1 × 109 CFU/ml bacteria). The bacteria were subsequently diluted to approximately 1 × 105 CFU/ml (5 × 104 CFU/well). The plates were incubated for 24 h at 37°C, in 5% CO2. After overnight growth, bacteria (10 μl of suspension from each well) were plated onto GCB agar and further incubated for another 24 h at 37°C, in 5% CO2. The MIC was defined as the lowest concentration of an antimicrobial that prevented visible growth on GCB agar plates. Time-kill curve analysis of antimicrobials against N. gonorrhoeae Method for time-kill curve analysis was adapted from Foerster et al. (Time-kill curve analysis and pharmacodynamic modelling for in vitro evaluation of antimicrobials against Neisseria gonorrhoeae. BMC Microbiol 16, 216 (2016)). The inoculum of N. gonorrhoeae strains was prepared in sterile PBS from cultures grown on GCB agar plates for 16–18 h at 37 °C, 5 % CO2. Bacterial suspensions in PBS were adjusted to ODA600 nm of 1.0 (equivalent to approximately 1 × 109 CFU/ml bacteria). For each strain, bacterial suspensions were diluted 1:10 into GW medium and 30 μl of this inoculum was diluted in 7.5 ml pre-warmed (37 °C) GW medium. For each test condition, 90 μl per well of this bacterial suspension was dispensed in round bottom 96-well Nunclon™ microtiter plates (ThermoFisher scientific). The plates were pre-incubated for 3 h shaking at 150 r.p.m, 37 °C, 5 % CO2. To each well containing pre-incubated bacteria, 110 μl of the antimicrobial diluted in GW medium or GW medium alone for a negative control was added to each well. Plates were incubated for a further 4 h with timepoints every 30 minutes. Samples (10 μl) for each condition were diluted 10-fold for 8 dilutions and plated onto GCB agar plates in triplicate. After 16-18 h incubation at 37 °C, 5 % CO2, bacterial CFU was calculated from the dilution containing 20-60 CFU. For antimicrobial peptide dose curves, bacteria were incubated in 11 different peptide concentrations with a final starting concentration of 50 μg/ ml and the inoculum was prepared in fresh, pre-warmed GW medium. The final concentration of mAb:peptide conjugates was 700 μg/ ml for FA1090 strains. Inoculum for mAb:peptide assays was prepared in GW medium which had been harvested from the respective bacterial strain grown for 24 h at 37 °C, 5 % CO2, prior to dialysis with slide-A-Lyzer dialysis cassette (20K MWCO, ThermoFisher scientific) into fresh GW medium to retain IgAP. Haemolysis assay Haemolytic activity of Oct-TriA1 analogues and APC’s was performed as previously described (Oddo, A. & Hansen, P. R. Hemolytic Activity of Antimicrobial Peptides. Methods Mol Biol 1548, 427-435 (2017)). In brief, Positive control wells were coated in 5 µM melittin (Merck Life Science UK Limited) overnight. Whole human blood (1 ml; K2EDTA; Cambridge Bioscience, UK) was washed three times with 4 ml PBS prior to centrifugation at 700 × g for 8 minutes; erythrocytes from the final wash were pelleted at 1,000 × g for 10 minutes. Erythrocytes were diluted to a final working concentration of 0.5% v/v. Peptides were added to 96-well V-bottomed polypropylene plates in two-fold dilutions (7 concentrations, 75 µl) with a final starting concentration of 200 μg/ ml or 2.8 mg/ ml; APCs were added to the wells at a final concentration of 1.4 mg/ ml. Mellitin (2.5 µM) was added as a positive control and PBS was added to negative control wells. Each sample and control were tested in triplicate. An equal volume of erythrocytes was added to each well and incubated at 37 °C for 1 h. Erythrocytes were subsequently pelleted at 1,000 × g for 10 minutes and supernatant (60 µl) transferred to 96-Well flat-bottomed polystyrene plates and absorbance was read at OD415 nm. Positive and negative controls were averaged and normalised to 100 and 0% haemolysis respectively; Percent haemolysis of peptides and APCs were calculated relative to the positive control. Cytotoxicity assay Cell culture: For the cytotoxicity assays, HK-2 cells (CRL-2190™; American Type Culture Collection) were seeded 24 hours prior to addition of Oct-TriA1 analogues or APCs in 96-well plates at a density of 2 × 104 cells/ well for approximately 80% confluency. Sample preparation: Oct-TriA1 analogues and APCs were added into each well with a final concentration gradient from 400 μg/ ml and 5.6 mg/ ml, to 25 μg/ ml and 350 μg/ ml in 2-fold dilutions, respectively. Each sample was performed in triplicate. Cells alone, media with peptides, Triton-X-100 (0.1%) and Digitonin (30 μg/ ml) were used as controls. The cells were incubated with the Oct-TriA1 analogues or APCs for 0, 4, 24 or 48 hours at 37 °C, 5% CO2. LDH assay: After incubation, 50 µl of culture medium was added to 50 µl of reaction mixture (Biovision LDH cytotoxicity assay kit) and incubated for 20 minutes at room temperature. The absorbance was read at OD490 nm using a Molecular devices SpectraMax M5 plate reader. LDH release was calculated as follows: % Total LDH leakage= ((Sample absorbance – Cell free sample)-mean media control absorbance/ Mean triton-X-100 positive control absorbance-mean media control absorbance) × 100. MTT assay: Using the same cell plate as for the LDH assay, remove all remaining media. Add 200 µl fresh cell media and 50 µl tetrazolium dye MTT, (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide, 5 mg/ ml) to all wells. Incubate at 37 °C, 5% CO2 for 3 hours prior to discarding all media. Subsequently, add 200 µl DMSO to each well along with 25 µl glycine buffer (0.1 M glycine, 0.1 M NaCl pH 10.5) and shake at 1000 r.p.m for 10 minutes. Absorbance was read at OD570 nm using a Molecular devices SpectraMax M5 plate reader. Cell viability = (Sample absorbance – cell free blank/ Mean media control absorbance) x100.
Table 4 m n 1
9
1 0
Sequences SEQ ID NO: 31 – IgAP from N. gonorrhoeae strain FA1090 >NEIS0651_IgAP_NMB0700_NGO0275 MKAKRFKINAISLSIFLAYALTPYSEAALVRDDVDYQIFRDFAENKGKFFVGATDLSVKN KRGQNIGNALSNVPMIDFSVADVNKRIATVVDPQYAVSVKHAKAEVHTFYYGQYNGHNDV ADKENEYRVVEQNNYEPHKAWGASNLGRLEDYNMARFNKFVTEVAPIAPTDAGGGLDTYK DKNRFSSFVRIGAGRQLVYEKGVYHQEGNEKGYDLRDLSQAYRYAIAGTPYKDINIDQTM NTEGLIGFGNHNKQYSAEELKQALSQDALTNYGVLGDSGSPLFAFDKQKNQWVFLGTYDY WAGYGKKSWQEWNIYKKEFADKIKQHDNAGTVKGNGEHHWKTTGTNSHIGSTAVRLANNE GDANNGQNVTFEDNGTLVLNQNINQGAGGLFFKGDYTVKGANNDITWLGAGIDVADGKKV VWQVKNPNGDRLAKIGKGTLEINGTGVNQGQLKVGDGTVILNQKADADKKVQAFSQVGIV SGRGTLVLNSSNQINPDNLYFGFRGGRLDANGNDLTFEHIRNVDEGARIVNHNTDHASTI TLTGKSLITNPNSLSVHSIQNDYDEDDYSYYYRPRRPIPQGKDLYYKNYRYYALKSGGSV NAPMPENGVAENNDWVFMGYTQEEAKKNAMNHKNNQRISGFSGFFGEENGKGHNGALNLN FNGKSAQNRFLLTGGANLNGKISVTQGNVLLSGRPTPHARDFVNKSSARKDAHFSKNNEV VFEDDWINRTFKAAEIAVNQSASFSSGRNVSDITANITATDNAKVNLGYKNGDEVCVRSD YTGYVTCNTGNLSDKALNSFDATRINGNVNLNQNAALVLGKAALWGKIQGQGNSRVSLNQ HSKWHLTGDSQVHNLSLADSHIHLNNASDAQSANKYHTIKINHLSGNGHFHYLTDLAKNL GDKVLVKESASGHYQLHVQNKTGEPNQEGLDLFDASSVQDRSRLFVSLANHYVDLGALRY TIKTENGITRLYNPYAGNRRPVKPAPSPAANTASQAQKATQTDGAQIAKPQNIVVAPPSP QANQAEEALRQQAKAEQVKRQQAAEAEKVARQKDEEAKRKAAEIARQQEEARKAAELAAK QKAEAERKARELARQKAEEASHQANAKPKRRRRRAILPRPPAPVFSLDDYDAKDNSESSI GNLARVIPRMGRELINDYEEIPLEELEDEAEEERRQATQFQPKSRNRRAISSEPSSDEDA SESVSTSDKHPQDNTELHEKVETAGLQPRAAQPRTQAAAQADAVSTNTNSALSDAMASTQ SILLDTGASLTRHIAQKSRADAEKNSVWMSNTGYGRDYASAQYRRFSSKRTQTQIGIDRS LSENMQIGGVLTYSDSQHTFDQAGGKNTFVQANLYGKYYLNDAWYVAGDIGAGSLRSRLQ TQQKANFNRTSIQTGLTLGNTLKINQFEIVPSAGIRYSRLSSADYKLGDDSVKVSSMAVK TLTAGLDFAYRFKVGNLTVKPLLSAAYFANYGKGGVNVGGKSFAYKADNQQQYSAGAALL YRNVTLNVNGSITKGKQLEKQKSGQIKIQIRF SEQ ID NO: 32 –IgA1 Protease from Neisseria meningitidis H4476 MKTKRFKINAISLSIFLAYALTPYSEAALVRDDVDYQIFRDFAENKGKFFVGATDLSVKNKQGQ NIGNALSNVPMIDFSVADVNRRTLTVIDPQYAVSVKHVKGDEISYYGHHNGHLDVSNDENEYR SVAQNDYEPNKNWHHGNQGRLEDYNMARLNKFVTEVAPIAPTSAGGGVETYKDKNRFSEFV RVGAGTQFEYNSRYNMTELSRAYRYAIAGTPYQDVNVTSNLNQEGLIGFGDNSKHHSPEKLKE VLSQNALTNYAVLGDSGSPLFAYDKQEKRWVFLGAYDYWAGYQKNSWQEWNIYKKEFADKI KQRDNAGTIKGNGEHHWNITFGTNSKIGSTAVRLAGNEKDANNGQNVTFEDNGTLVLDQNIN QGAGGLFFKGDYTVKGINNDITWLGAGIDVTDGKKVVWQVKNPNGDRLAKIGKGTLEINGTG VNQGQLKVGDGTVILNQQADADKKVQAFSQVGIVSGRGTLVLNSSNQINPDNLYFGFRGGRL DANGNDLTFEHIRNVDEGARIVNHNTSHASTITLTGKSLITNPNSLSVHSIQNDYDEDDYSYYY RPRRPIPQGKDLYYKNYRYYALKSGGSVNAPMPENGVTENNDWVFMGYTQEEAKKNAMNH KNNQRISGFSGFFGEENGKGHNGALNLNFNGKSAQNRFLLTGGTNLNGKISVTQGNVLLSGRP TPHARDFVNKSSARKDAHFSKNNEVVFEDDWINRTFKAAEIAVNQSASFSSGRNVSNITANITA TDNAKVNLGYKNGDEVCVRSDYTGYVTCNTGNLSDKALNSFGATQINGNVNLNQNAALVLG KAALWGQIQGQGNSRVSLNQHSKWHLTGDSQVHNLSLADSHIHLNNASDAQSANQYHTLKIN HLSGNGHFHYLTHLAENLGDKVLVKESASGHYQLHVQDKTGEPNQEGLNLFDASSVQDRSRL SVSLANNHVDLGALRYTIKTENGITRLYNPYAENRRRVKPVPSPATNTASQAQTDSAQIAKPQN IVVAPPSPQANQAEEAKRQQAKAEQVKRQQAEAERKSAELAKQKAEAEREARELATRQKAEQ ERSSAELARRHEKEREAAELSAKQKVEAEREAQALAVRRKAEAEEAKRQAAELARQQEEARK AAELAAKQKAETERKAAEIAEQKAEAEREAAELAKQKAEEEGRQAAQSQPKRRNRRAIPPELS SDATTRALPRIARNSNPDASDYEEIPLDALEDEDVSESVDTSDKQPQDNTELHEKVETVSLQPR AAQPRAQAAAQPQAQAAAQPQAQAVAQADAVSTNTNSALSDAMASTQSILLDTGASLTRHIA QKSRADAEKNSVWMSNIGYGRDYASAQYRRFSSKRTQTQIGIDRSLSENMQIGGVLTYSDSQH TFDQASGKNTFVQANLYGKYYLNDAWYVAGDIGAGSLRSRLQTQQKANFNRTSIQTGLTLGN TLKINQFEIVPSAGIRYSRLSSADYKLGNDSVKVSSMSVKTLTAGLDFAYRFKVGNLTVKPLLS AAYFANYGKGGVNVGGNSFAYKADNQQKYSAGAALLYRNVTLNVNGSITKGKQLEKQKSGQ IKIQIRF SEQ ID NO: 33 - IgA1 Protease from Haemophilus Influenza HK61 1 mlnkkfklnf ialtvayalt pyteaalvrd dvdyqifrdf aenkgkfsvg atnvevrdkk 61 nqslgsalpn gipmidfsvv dvdkriatlv npqyvvgvkh vsngvselhf gnlngnmnng 121 nakshrdvss eenryytvek nnfptenvts fttkeeqdaq krredyympr ldkfvtevap 181 ieastannnk geynnsdkyp afvrlgsgsq fiykkgsryq liltekdkqg nllrnwdvgg 241 dnlelvgnay tygiagtpyk vnhennglig fgnskeehsd pkgilsqdpl tnyavlgdsg 301 splfvydrek gkwlflgsyd fwagynkksw qewniykhef aekiyqqysa gsltgsntqy 361 twqatgstst itgggeplsv dltdgkdkpn hgksitlkgs gtltlnnhid qgagglffeg 421 dyevkgtsds ttwkgagvsv adgktvtwkv hnpkydrlak igkgtlvveg kgknegllkv 481 gdgtvilkqk adannkvqaf sqvgivsgrs tlvlnddkqv dpnsiyfgfr ggrldlngns 541 ltfdhirnid dgarvvnhnm tntsnititg eslitnpnti tsynieaqdd dhplrirsip 601 yrqlyfnqdn rsyytlkkga strselpqns gesnenwlym grtsdeakrn vmnhinnerm 661 ngfngyfgee etkatqngkl nvtfngksdq nrflltggtn lngdlnvekg tlflsgrptp 721 hardiagiss tkkdphften nevvveddwi nrnfkattmn vtgnaslysg rnvanitsni 781 tasnnaqvhi gyktgdtvcv rsdytgyvtc hnsnlsekal nsfnptnlrg nvnltenasf 841 tlgkanlfgt iqsigtsqvn lkenshwhlt gnsnvnqlnl tnghihlnaq ndankvttyn 901 tltvnslsgn gsfyywvdft nnksnkvvvn ksatgnftlq vadktgepnh neltlfdasn 961 atrnnlevtl angsvdrgaw kyklrnvngr ydlynpevek rnqtvdttni ttpndiqada 1021 psaqsnneei arvetpvppp apatesaias eqpetrpaet aqpameetnt anstetapks 1081 dtatqtenpn sesvpsette kvaenppqen etvakneqea teptpqngev akedqptvea 1141 ntqtneatqs egkteetqta etkseptesv tvsenqpekt vsqstedkvv vekeekakve 1201 teetqkapqv tskeppkqae papeevptdt naeeaqalqq tqpttvaaae ttspnskpae 1261 etqqpsektn aepvtpvvse ntatqptete etakvekekt qevpqvasqe spkqeqpaak 1321 pqaqtkpqae parenvlttk nvgepqpqaq pqtqstavpt tgetaanskp aakpqaqakp 1381 qteparenvs tvntkepqsq tsatvsteqp aketssnveq papensintg sattmtetae 1441 ksdkpqmetv tendrqpean tvadnsvann sessesksrr rrsvsqpket saeettvast 1501 qettvdnsvs tpkprsrrtr rsvqtnsyep velptenaen aenvqsgnnv ansqpalrnl 1561 tskntnavls navakaqfva lnvgkavsqh isqlemnneg qynvwisnts mnknysseqy 1621 rrfsskstqt qlgwdqtisn nvqlggvfty vrnsnnfdka sskntlaqvn fyskyyadnh 1681 wylgidlgyg kfqsnlqtnn nakfarhtaq igltagkafn lgnfavkptv gvrysylsna 1741 dfalaqdrik vnpisvktaf aqvdlsytyh lgefsitpil sarydanqgn gkinvsvydf 1801 aynvenqqqy naglklkyhn vklsligglt kakqaekqkt aevklsfsf SEQ ID NO: 34 - IgA1 Protease from Streptococcus pneumonia P1031 1 mekyfgekqe rfsfrklsvg lvsatisslf fmsvlasssv daqetagvhy kyvadselss 61 eekkqlvydi ptyvenddet yylvyklnsq nqlaelpntg sknerqalvs gaslaalgil 121 ifavskkkvk nktvlhlvlv agmgngvlvs vhalenhlll nyntdyelts geklplpkei 181 sgytyigyik egkttsdfev snqeksaatp tkqqkvdynv tpnfvdhpst vqaiqeqtpv 241 sstkptevqv vekpfsteli nprkeekqss dsqeqlaehk nletkkeeki spkektgvnt 301 lnpqdevlsg qlnkpellyr detietkidf qeeiqenpdl aegtvrvkqe galgkkveiv 361 rifsvnneev sreiiststt apvsrivekg tkkaqvikeq aetgaehkev qsgaivepai 421 qpelpaavlt dkgesavqpe lpeavvsdkg vpevqpalpe avmtdkgdpe qveplpeytg 481 vqagaivepe kvepeyagvq agaivepeqv aplpeytgvq agaivepekv eapkeytgvq 541 agaivepekv eapkeytgvq agaivepekv epskeytgvq agaivepeqi aplpeytgvq 601 agaivepekv ealkeytgki eqpsaedtkp nnentntpee msiqkkssal inmnfitdss 661 kvtgvgsatf iapnvlltva hnfinnstdn ttgefrgdks knvyewvtpd gqkgtftann 721 ihfynkkdyp kgfiydlavi klpettgreh velvknyskv nlndklnvhg ypagkythlk 781 datvemeqey anntygvqyq ggnpgmsggg ifnangevig vhqngaqnrs gglilsptql 841 awiksiiagn eippvydely rhkdekkdda kdekevikkl elrnissvel yskdgnkyrh 901 vtslaslpsn aenyfmkvks enfkdvmlpv tsitndtkdn rdvykivasa nsliqhennn 961 vlenytyylp ktqqsetgvy tsfknlvdam nsnpngtfrl gatmdareve lpdgqesyvn 1021 nvfhgilvgt nnekyyaiyn lkkplfgeln gatveklslk dvnisakddt atlakeannn 1081 thidnvhadg aiagersigg lvsqvnnsti snssytgrit ntyktvasyq igglvgklsg 1141 prglidksfa sidlssnatq gdqsiggivg avensalisn syaegnlnnv qrfanvggvv 1201 gnlwdpvggl eksgrlsnvl sdvnvtngna iagynfngik angtysnknn kvvnvvqedd 1261 eiltkdstvq rgevledaqi kekkatfvsk ntiktedfnf ssryvtdykn lenadsskek 1321 vykniekllp fynretivky gnlvetssnl ynkellsvvp mkdkevisdi nknkssinkl 1381 llyyadntse tlnvnyqtdf snvaeyrigg tnliytpntl lrnyqnilde vlpalnsvey 1441 kseairkvld vskdvsltel yleeqfnttk tnlkdsltkl ltadaaiaen nnkvidnyvi 1501 ekiknnkeal llgltylerw ydfkyrdtka kdlvmyhldf fgksnssald nvielgksgy 1561 nnllaknnvi tynvllakny ktnnlfdale kyrkafvpdk tnnewfkeqt kayiveekst 1621 ikevsdkqsi agspysigvy drltspswky psmvlplltl peksvfiian istigfgayd 1681 ryrskehpag tdlndyvekk akeaavrfrd hydywyrild dknkeklyrs vlvydafrfg 1741 tdekedkdty qatfetnhpa ikhffgpagn nvvhnsngay atgdafyyma yrmldkdgav 1801 tythemthns dreiylggyg rrnglgpefy akgllqapdh pndptvtins ilkydqsees 1861 trlqvadptq rfgsvddlnk ymhnmfdviy mleilegkav akldtnqkyd llrkieneyk 1921 pdpdgnsvya tnvvrrlkpe eltklttfns liehdiitrr gyvdeatykr ngyytinlfs 1981 piysalsski gtpgdlmgrr iafellaakg ykdgmvpyis nqyekeakaq gkvitsygkq 2041 iglvtdeivl skvfnnqyns widfkkdmyk eredkfgkln kvsfidpngs warqqkvtid 2101 ninrlekmie davkfdaede vaklypetns rvlklkkaif kayldqtgdf rssifenk SEQ ID NO: 35 – LasA from Pseudomonas aeruginosa FRD2 1 mqhkrsrama sprspflfvl lalavggtan ahddglpafr ysaellgqlq lpsvalplnd 61 dlflygrdae afdleaylav napalrdkse ylehwsgyys inpkvlltlm vmqsgplgap 121 deralaaplg rlsakrgfda qvrdvlqqls rryygfeeyq lrqaaarkav gedglnaasa 181 allgllrega kasavqggnp lgayaqtfqr lfgtpaaell qprnrvarql qakaalapps 241 nlmqlpwrqg yswqpngahs ntgsgypyss fdasydwprw gsatysvvaa hagtvrvlsr 301 cqvrvthpsg watnyyhmdq iqvsngqqvs adtklgvyag nintalcegg sstgphlhfs 361 llyngafvsl qgasfgpyri nvgtsnydnd crryyfynqs agtthcafrp lynpglal
The following are numbered aspects of the invention 1. An antimicrobial agent comprising a) a microbe-targeting moiety; b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker. 2. An antimicrobial agent according to aspect 1, wherein said microbe expresses one or more proteins capable of cleaving said linker and said linker is cleaved by said one or more proteins 3. An antimicrobial agent according to any one of the preceding aspects, wherein said microbe expresses a protease and said linker comprises a protease recognition sequence specific for said protease; preferably wherein: (i) said protease is a serine protease, wherein said protease is preferably an IgA specific serine protease and/or is of E.C. class 3.4.21 or 3.4.24, preferably 3.4.21, more preferably of E.C. class 3.4.21.72; and/or (ii) said protease has an amino acid sequence at least 70% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34 or SEQ ID NO: 35. 4. An antimicrobial agent according to any one of the preceding aspects, wherein said linker comprises a peptide of from about 5 to about 50 amino acids in length; wherein said linker comprises a protease recognition site capable of being cleaved by the protease of aspect 3. 5. An antimicrobial agent according to any one of the preceding aspects, wherein said protease recognition site is a group of formula [PRS], wherein said group of formula [PRS] is a group of formula [PRS1] or [PRS2]: Yaa – Pro – Xaa – Pro [PRS1] Gly – Gly– Ala [PRS2] wherein: Yaa is selected from Arg-Pro; Thr-Pro; Ala-Pro; Gly-Pro; and Pro; and Xaa is selected from Thr; Ser and Ala. 6. An antimicrobial agent according to any one of the preceding aspects, wherein the linker comprises a group of formula (I): (Aaa)n – [PRS] – (Baa)m (I) wherein: each Aaa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; each Baa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; n is an integer from 1 to 10; preferably from 1 to 6 and m is an integer from 1 to 10; preferably from 1 to 6. 7. An antimicrobial agent according to any one of the preceding aspects, comprising a group of formula (II): D – X – (Aaa)n – [PRS] – (Baa)m – Y – Caa (II) wherein: - D is the antimicrobial moiety; - X is absent or is a spacer group; - Y is absent or is a spacer group; - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on said microbe-targeting moiety. 8 An antimicrobial agent according to aspect 8, wherein: - X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta- alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2-aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13- tetraoxapenta-decanoic acid); preferably O2Oc; - Y is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta- alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2-aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13- tetraoxapenta-decanoic acid); preferably O2Oc; and - Caa is selected from Cys, Lys, Met, Ser, Thr, Arg. 9. An antimicrobial agent according to any one of the preceding aspects, comprising a group of formula (III): D – X – Aaa1 – Aaa2 – Aaa3 – [PRS] – Baa1 – Baa2 – Baa3 – Y – Caa (III) wherein: - Aaa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; and - Baa3 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; and - D, X, Y and Caa are as defined in any of aspects 7 to 8. 10. An antimicrobial agent according to aspect 9, wherein: - X is absent or is O2Oc (8-amino-3,6-dioxaoctanoic acid), PEG3 (12-amino-4,7,10- trioxadodecanoic acid) or PEG4 (15-amino-4,7,10,13-tetraoxapenta-decanoic acid); preferably O2Oc; - Aaa1 is selected from Val, Leu, Pro, and Arg; - Aaa2 is selected from Val, Leu, Pro, and Arg; - Aaa3 is absent or is selected from Val, Leu, Pro and Arg; - Baa1 is selected from Val, Ala, Gln, Asn, Phe, and Ser,; - Baa2 is selected from Val, Ala, Gln, Asn, Phe, and Ser; - Baa3 is selected from Val, Ala, Gln, Asn, Phe, and Ser; and - Baa4 is selected from Val, Ala, Gln, Asn, Phe, and Ser. 11. An antimicrobial agent according to any one of the preceding aspects, wherein the antimicrobial moiety is an antibiotic compound. 12. An antimicrobial agent according to aspect 11, wherein the antibiotic compound is selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides. 13. An antimicrobial agent according to any one of the preceding aspects, wherein the antimicrobial moiety is an antimicrobial peptide which is a N-acylated tridecapeptide or N- acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C4-12 alkyl, C4-12 alkenyl, or C4-12 alkynyl group which is unsubstituted or which is substituted with 1, 2 or 3 substituents selected from CO, -ORa, -N(Ra)2, halogen, and -CN and each Ra which may be the same or different is selected from H and unsubstituted C1-2 alkyl, preferably H. 14. An antimicrobial agent according to any one of aspects 12 to 13, wherein the antimicrobial peptide is octyl-tridecaptin A1 or a variant thereof comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1. 15. An antibody capable of specifically binding to MtrE, comprising: (a) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 22 to 24 and 26 to 28, respectively; (b) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 2 to 4 and 6 to 8, respectively; or (c) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 12 to 14 and 16 to 18, respectively. 16. An antibody that binds to the same epitope or competes with the antibody of aspect 15. 17. The antibody according to any one of aspects 15 to 16, comprising: i) a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 21, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 25; or ii) a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 1, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 5; or iii) a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 11, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 15. 18. An antimicrobial agent according to any one of aspects 1 to 14, wherein the microbe-targeting moiety is an antibody according to any one of aspects 15 to 17. 19. One or more polynucleotides encoding the antibody according to any one of aspects 15 to 17, one or more vectors comprising said polynucleotides, or a host cell comprising said vectors. 20. A method for producing an antibody of any one of aspects 15 to 17 that is capable of specifically binding to MtrE, comprising culturing the host cell of aspect 19 and isolating the antibody from said culture. 21. A pharmaceutical composition comprising an antimicrobial agent according to any one of aspects 1 to 14 or 18 or an antibody of any one of aspects 15 to 17 and one or more pharmaceutically acceptable excipient, carrier or diluent. 22. An antimicrobial agent according to any one of aspects 1 to 14 or 18, an antibody of any one of aspects 15 to 17 or a composition according to aspect 21 for use in medicine. 23. An antimicrobial agent according to any one of aspects 1 to 14 or 18, an antibody of any one of aspects 15 to 17 or a composition according to aspect 21 for use in treating or preventing bacterial infection in a subject in need thereof. 24. An antimicrobial agent, antibody or composition for use according to aspect 23, wherein: - said bacterial infection is caused by Gram-negative bacteria; - said bacterial infection is caused by bacteria of family Neisseriaceae, Streptococcaceae, Pasteurellaceae and/or Pseudomonadaceae, preferably Neisseriaceae. - said bacterial infection is caused by Neisseria gonorrhoeae (N gonorrhoeae) or Neisseria meningitides (N meningitides), preferably N gonorrhoeae; or - said bacterial infection is caused by antibiotic resistant Neisseria gonorrhoeae, preferably Multi-Drug Resistant Neisseria gonorrhoeae. 25. An antimicrobial agent, antibody or composition for use according to any one of aspects 23 to 24, wherein said use comprises treating or preventing gonorrhoea, disseminated gonorrhoea, disseminated gonococcemia, septic arthritis, gonococcal ophthalmia neonatorum, pelvic inflammatory disease, ectopic pregnancy, pelvic scarring (including infertility arising from pelvic scarring), pharyngitis, proctitis, HIV, meningitis, meningococcemia, septicaemia, pneumonia, otitis media, pericarditis, epiglottitis, septic arthritis, cellulitis, and osteromyelitis, septic shock (e.g. associated with ecthyma gangrenosum), urinary tract infection, gastrointestinal infection, necrotising enterocolitis, and skin and soft tissue infections (e.g. hemorrhage and necrosis). 26. A protease-cleavable oligopeptide comprising a group of formula (Aaa)n – [PRS] – (Baa)m – Y – Caa wherein - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on a microbe-targeting moiety such as an antibody; and - [PRS], (Aaa), (Baa), n, m and Y are as defined in any one of aspects 6 to 14. 27. Use of a protease-cleavable oligopeptide as defined in aspect 26 to conjugate a microbe-targeting moiety to an antimicrobial moiety, wherein said microbe-targeting moiety and said antimicrobial moiety are preferably as defined in any one of aspects 11 to 18. 28. A method of identifying the presence of bacteria (e.g. N.gonorrhoeae) or a protein or a protein fragment thereof, in a sample using an antimicrobial agent according to any one of aspects 1 to 14 or 18, or an antibody of any one of aspects 15 to 17; optionally comprising contacting said sample with said antimicrobial agent or antibody and determining the extent of bacterial cell killing.

Claims

CLAIMS 1. An antimicrobial agent comprising a) a microbe-targeting moiety; b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker.
2. The antimicrobial agent according to claim 1, wherein said microbe expresses one or more proteins capable of cleaving said linker and said linker is cleaved by said one or more proteins.
3. The antimicrobial agent according to claim 1 or claim 2, wherein said microbe expresses a protease and said linker comprises a protease recognition sequence specific for said protease. 4. The antimicrobial agent according to any one of the preceding claims, wherein said protease is a serine protease, wherein said protease is preferably an IgA specific serine protease and/or is of E.C. class 3.4.21 or 3.4.24, preferably 3.4.21, more preferably of E.C. class 3.
4.21.72.
5. The antimicrobial agent according to any one of the preceding claims, wherein said protease has an amino acid sequence at least 70% identical to the amino acid sequence of any one of SEQ ID NOs: 31 to 34 or SEQ ID NO: 35.
6. The antimicrobial agent according to any one of the preceding claims, wherein said linker comprises a peptide of from about 5 to about 50 amino acids in length; wherein preferably said linker comprises a peptide of from about 8 to about 20 amino acids in length.
7. The antimicrobial agent according to any one of the preceding claims, wherein said linker comprises a protease recognition site capable of being cleaved by the protease of one of claims 3-5.
8. The antimicrobial agent according to any one of the preceding claims, wherein said protease recognition site is a group of formula [PRS], wherein said group of formula [PRS] is a group of formula [PRS1] or [PRS2]: Yaa – Pro – Xaa – Pro [PRS1] Gly – Gly– Ala [PRS2] wherein: Yaa is selected from Arg-Pro; Thr-Pro; Ala-Pro; Gly-Pro; and Pro; and Xaa is selected from Thr; Ser and Ala.
9. The antimicrobial agent according to any one of the preceding claims, wherein the linker comprises a group of formula (I): (Aaa)n – [PRS] – (Baa)m (I) wherein: each Aaa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; each Baa, which may be the same or different, is independently selected from natural and non-natural amino acids; preferably from L- and D- isomers of natural amino acids; n is an integer from 1 to 10; preferably from 1 to 6 and m is an integer from 1 to 10; preferably from 1 to 6.
10. The antimicrobial agent according to any one of the preceding claims, comprising a group of formula (II): D – X – (Aaa)n – [PRS] – (Baa)m – Y – Caa (II) wherein: - D is the antimicrobial moiety; - X is absent or is a spacer group; - Y is absent or is a spacer group; - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on said microbe-targeting moiety.
11 The antimicrobial agent according to claim 10, wherein: - X is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta- alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2-aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13- tetraoxapenta-decanoic acid); preferably O2Oc; - Y is absent or is selected from O2Oc (8-amino-3,6-dioxaoctanoic acid), beta- alanine, O1Pen (5-amino-3-oxapentanoic acid), AEA ((2-aminoethoxy)acetic acid), Ava (5-aminovaleric acid), Ahx (6-aminohexanoic acid), GABA (4-aminobutyric acid), Ttds (trioxatridecan-succinamic acid)), and PEGs (polyethylene glycols) such as PEG3 (12-amino-4,7,10-trioxadodecanoic acid) and PEG4 (15-amino-4,7,10,13- tetraoxapenta-decanoic acid); preferably O2Oc; and - Caa is selected from Cys, Lys, Met, Ser, Thr, Arg.
12. The antimicrobial agent according to any one of the preceding claims, comprising a group of formula: D – X – Aaa1 – Aaa2 – Aaa3 – [PRS] – Baa1 – Baa2 – Baa3 – Y – Caa (III) wherein: - Aaa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Aaa3 is absent or is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa1 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; - Baa2 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; and - Baa3 is selected from Val, Leu, Ile, Ala, Ser, Thr, Met, Tyr, Pro, Gln, Asn, Phe, Arg and Lys; and - D, X, Y and Caa are as defined in any of claims 10 to 11. 13. The antimicrobial agent according to claim 12, wherein: - X is absent or is O2Oc (8-amino-3,6-dioxaoctanoic acid), PEG3 (12-amino-4,7,10- trioxadodecanoic acid) or PEG4 (15-amino-4,7,10,
13-tetraoxapenta-decanoic acid); preferably O2Oc; - Aaa1 is selected from Val, Leu, Pro, and Arg; - Aaa2 is selected from Val, Leu, Pro, and Arg; - Aaa3 is absent or is selected from Val, Leu, Pro and Arg; - Baa1 is selected from Val, Ala, Gln, Asn, Phe, and Ser,; - Baa2 is selected from Val, Ala, Gln, Asn, Phe, and Ser; - Baa3 is selected from Val, Ala, Gln, Asn, Phe, and Ser; and - Baa4 is selected from Val, Ala, Gln, Asn, Phe, and Ser.
14. The antimicrobial agent according to any one of claims 8 to 13, wherein said [PRS] is a group of formula [PRS1].
15. The antimicrobial agent according to any one of the preceding claims, wherein the antimicrobial moiety is an antibiotic compound.
16. An antimicrobial agent according to claim 15, wherein the antibiotic compound is selected from antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and aminoglycosides.
17. The antimicrobial agent according to any one of the preceding claims, wherein the antimicrobial moiety is an antimicrobial peptide; preferably wherein the antimicrobial peptide is an N-acylated tridecapeptide or N- acylated tridecalipopeptide (e.g. TriA1, TriB1, TriM1 and derivatives thereof); microcin and derivatives thereof such as microcin N, bacitracin, boceprevir, dalbavancin, daptomycin, enfuvirtide, oritavancin, teicoplanin, telaprevir, telavancin, vancomycin, guavanin (e.g. guavanin 2), a polymixin, an octapeptin, a surfactin, a lichenysin, brevicidine, lacterocidine or daptomycin.
18. The antimicrobial agent according to any one of the preceding claims, wherein the antimicrobial moiety is an antimicrobial peptide which is a N-acylated tridecapeptide or N- acylated tridecalipopeptide; wherein the N terminal group with which the trideca(lipo)peptide is acylated is a C4-12 alkyl, C4-12 alkenyl, or C4-12 alkynyl group which is unsubstituted or which is substituted with 1, 2 or 3 substituents selected from CO, -ORa, -N(Ra)2, halogen, and -CN and each Ra which may be the same or different is selected from H and unsubstituted C1-2 alkyl, preferably H.
19. The antimicrobial agent according to any one of claims 16 to 18, wherein the antimicrobial peptide is octyl-tridecaptin A1 or a variant thereof comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1.
20. The antimicrobial agent according to claim 19, wherein the antimicrobial peptide is octyl-tridecaptin A1.
21. The antimicrobial agent according to any one of the preceding claims, wherein the microbe is a bacterium of family Neisseriaceae, Streptococcaceae, Pasteurellaceae and/or Pseudomonadaceae, preferably Neisseria gonorrhoeae.
22. The antimicrobial agent according to any one of the preceding claims, comprising a) a microbe-targeting moiety b) a linker selectively cleavable by said microbe; and c) an antimicrobial moiety; wherein the linker and antimicrobial moiety are comprised in a moiety of form D – X – Aaa1 – Aaa2 – Aaa3 – Yaa – Pro – Xaa – Pro – Baa1 – Baa2 – Baa3 – Y – Caa wherein D is the antimicrobial moiety; X is absent or is O2Oc; Aaa1 is Val or Leu; Aaa2 is Val or Pro; Aaa3 is absent or is Arg; Yaa is Ala-Pro or Pro; Xaa is Ser or Ala; Baa1 is Gln or Val; Baa2 is Ala or Phe; Baa3 is Asn or Ser; Y is absent or is O2Oc and Caa is Cys or Lys; wherein the antimicrobial moiety (D) is Oct-TriA1 or a variant thereof comprising from 1 to 5 substitutions in the amino acid sequence of tridecaptin A1; and wherein the microbe-targeting moiety is conjugated to the antimicrobial moiety by the linker; wherein the linker-antimicrobial moiety is covalently attached to the microbe-targeting moiety by a covalent attachment between Caa and the microbe-targeting moiety.
23. An antibody capable of specifically binding to MtrE, comprising: (a) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 22 to 24 and 26 to 28, respectively; (b) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 2 to 4 and 6 to 8, respectively; or (c) CDRH1, CDRH2, CDRH3, CDRL1, CDRL2 and CDRL3 as set out in SEQ ID NOs: 12 to 14 and 16 to 18, respectively.
24. An antibody that binds to the same epitope or competes with the antibody of claim 23.
25. The antibody according to claim 23 or 24, capable of specifically binding to N. gonorrhoeae.
26. The antibody according to any one of claims 23 to 25, comprising a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 21, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 25.
27. The antibody according to any one of claims 23 to 26, comprising a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 1, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 5.
28. The antibody according to any one of claims 23 to 27, comprising a heavy chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 11, and/or a light chain variable domain having ≥80%, ≥90%, ≥95%, ≥96%, ≥97%, ≥98%, ≥99% or 100% sequence identity to SEQ ID NO: 15.
29. The antibody according to any one of claim 23 to 26, wherein the antibody is mAb184a-D10.
30. The antibody according to any one of any one of claims 23 to 29, which is a full- length antibody, e.g. comprising a IgG1 constant region.
31. A combination of antibodies comprising two or more antibodies according to any one of claims 23 to 30.
32. The antimicrobial agent according to any one of claims 1 to 22, wherein the microbe-targeting moiety is an antibody according to any one of claims 23 to 30.
33. One or more polynucleotides encoding the antibody according to any one of claims 23 to 30, one or more vectors comprising said polynucleotides, or a host cell comprising said vectors.
34. A method for producing an antibody of any one of claims 23 to 30 that is capable of specifically binding to MtrE, comprising culturing the host cell of claim 32 and isolating the antibody from said culture.
35. A pharmaceutical composition comprising an antimicrobial agent according to any one of claims 1 to 22 or 32 or an antibody of any one of claims 23 to 31 and one or more pharmaceutically acceptable excipient, carrier or diluent.
36. The antimicrobial agent according to any one of claims 1 to 22 or 32, an antibody of any one of claims 23 to 31 or a composition according to claim 35 for use in medicine.
37. The antimicrobial agent according to any one of claims 1 to 22 or 32, an antibody of any one of claims 23 to 31 or a composition according to claim 35 for use in treating or preventing microbial infection in a subject in need thereof.
38. The antimicrobial agent according to any one of claims 1 to 22 or 32, an antibody of any one of claims 23 to 31 or a composition according to claim 35 for use in treating or preventing bacterial infection in a subject in need thereof.
39. The antimicrobial agent, antibody or composition for use according to claim 38, wherein said bacterial infection is caused by Gram-negative bacteria.
40. The antimicrobial agent, antibody or composition for use according to claim 38 or 39, wherein said bacterial infection is caused by bacteria of family Neisseriaceae, Streptococcaceae, Pasteurellaceae and/or Pseudomonadaceae, preferably Neisseriaceae.
41. The antimicrobial agent, antibody or composition for use according to any one of claims 38 to 40, wherein said bacterial infection is caused by Neisseria gonorrhoeae (N gonorrhoeae) or Neisseria meningitides (N meningitides), preferably N gonorrhoeae.
42. The antimicrobial agent, antibody or composition for use according to any one of claims 38 to 41, wherein said bacterial infection is caused by antibiotic resistant Neisseria gonorrhoeae, preferably wherein said antibiotic resistant Neisseria gonorrhoeae is resistant to one or more antimicrobial peptides, carbapenems, penicillins, cephalosporins, penems, tetracyclines, quinolones, lincomycins, macrolides, sulphonamides, glycopeptides, and/or aminoglycosides.
43. The antimicrobial agent, antibody or composition for use according to any one of claims 38 to 42, wherein said bacterial infection is caused by Multi-Drug Resistant Neisseria gonorrhoeae.
44. The antimicrobial agent, antibody or composition for use according to any one of claims 36 to 43, wherein said use comprises treating or preventing gonorrhoea, disseminated gonococcemia, septic arthritis, gonococcal ophthalmia neonatorum, pelvic inflammatory disease, ectopic pregnancy, pelvic scarring (including infertility arising from pelvic scarring), pharyngitis, proctitis, HIV, meningitis, meningococcemia, septicaemia, pneumonia, otitis media, pericarditis, epiglottitis, septic arthritis, cellulitis, and osteromyelitis, septic shock (e.g. associated with ecthyma gangrenosum), urinary tract infection, gastrointestinal infection, necrotising enterocolitis, and skin and soft tissue infections (e.g. hemorrhage and necrosis).
45. A kit, comprising antimicrobial agent according to any one of claims 1 to 22 or 32, an antibody of any one of claims 23 to 31 or a composition according to claim 35 together with instructions for use.
46. A method of making an antimicrobial agent according to any one of claims 1 to 22 or 32, comprising conjugating an antimicrobial moiety to a microbe-targeting moiety via a linker, wherein said linker is selectively cleavable by said microbe.
47. The method according to claim 46, wherein said antimicrobial moiety, said linker and/or said microbe-targeting moiety is as defined in any one of claims 6 to 30.
48. A protease-cleavable oligopeptide comprising a group of formula (Aaa)n – [PRS] – (Baa)m – Y – Caa wherein - Caa is a natural or non-natural amino acid having a reactive side chain capable of binding to a reactive functional group on a microbe-targeting moiety such as an antibody; and - [PRS], (Aaa), (Baa), n, m and Y are as defined in any one of claims 6 to 14.
49. Use of a protease-cleavable oligopeptide as defined in claim 48 to conjugate a microbe-targeting moiety to an antimicrobial moiety, wherein said microbe-targeting moiety and said antimicrobial moiety are preferably as defined in any one of claims 15 to 30.
50. A method of identifying the presence of bacteria (e.g. N.gonorrhoeae) or a protein or a protein fragment thereof, in a sample using an antimicrobial agent according to any one of claims 1 to 22 or 32, an antibody of any one of claims 23 to 31; optionally comprising contacting said sample with said antimicrobial agent or antibody and determining the extent of bacterial cell killing.
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