CN116159144A

CN116159144A - Antibacterial composition

Info

Publication number: CN116159144A
Application number: CN202111405220.9A
Authority: CN
Inventors: 刘润辉; 马鹏程; 武月铭
Original assignee: East China University of Science and Technology
Current assignee: East China University of Science and Technology
Priority date: 2021-11-24
Filing date: 2021-11-24
Publication date: 2023-05-26

Abstract

The present invention relates to an antimicrobial composition comprising a polypeptide polymer in combination with an antibiotic or a medicinal plant extract. The polypeptide polymer can be used with various antibiotics or medicinal plant extracts to improve in vivo and in vitro antibacterial effects. The presence of the polypeptide polymer can greatly reduce the amount of antibiotic, wherein the amount of antibiotic can be reduced by 250 times in some compositions. The composition can expand the antibacterial spectrum of antibiotics, save the antibacterial activity of antibiotics on drug-resistant strains, relieve the toxic and side effects of drugs, and simultaneously can be combined with medicinal plant extracts to promote the overall antibacterial effect, thereby providing a new choice for preventing and treating bacterial and/or fungal infectious diseases.

Description

Antibacterial composition

Technical Field

The invention relates to the technical field of antibiosis. In particular to a polypeptide polymer and antibiotics or medicinal plant extracts which are used for improving the antibacterial effect and are applied to the field of preventing and treating bacterial and/or fungal infection diseases.

Background

Microbial infection is a major cause of infectious disease in humans. The development of human beings is struggling with microorganisms, but the mortality rate after microbial infection is high due to no effective measures. Until 1928 fleming discovered penicillin and opened up a new era of treatment of microbial infections with antibiotics. Then various novel antibiotics are largely developed, so that the occurrence of microbial infection diseases is effectively controlled at one time, and the mortality rate of microbial infection is greatly reduced. However, the use of antibiotics in large quantities has also revealed a serious problem, namely the development of microbial resistance. Antibiotics are prone to induce microorganisms to develop resistance after continuous use due to their specific antibacterial mechanisms, making the original effective antibiotics ineffective. As early as 1940, the literature reports that microorganisms generate drug resistance, and the generation speed of the drug resistance of the microorganisms is continuously improved in the process of using a large amount of antibiotics, and methicillin-resistant staphylococcus aureus (MRSA), vancomycin-resistant staphylococcus aureus (VRSA), vancomycin-resistant enterococcus faecium (VRE) and the like which are clinically more toxic are sequentially presented. These resistant strains and genes are widely spread from person to person, and from person to animal. When the drug-resistant bacteria are infected, the effective treatment effect of various antibiotics cannot be achieved. Studies have shown that by 2050 humans die from drug-resistant bacterial infection to 1000 tens of thousands of people, even more than cancer, without effective measures. Currently, the number of effective antibiotics available for human use is decreasing, while on the other hand, the number of new antibiotics available for clinical use is increasingly decaying.

While antibiotic therapy remains the primary treatment for microbial infections, alternatives to antibiotics are also being studied extensively. Host defensin peptides are widely distributed in various living organisms, with good biosafety and broad-spectrum antibacterial activity. Meanwhile, the unique membrane rupture mechanism for sterilizing by destroying the cell membrane of the microorganism has the advantage of difficult drug resistance generation. There are also some host defensin peptides that have been entered into clinical trials. However, host defensin peptides have limited practical application due to the drawbacks of cumbersome synthesis, high cost, insufficient activity, etc. The polypeptide polymer has the characteristics of high efficiency, broad-spectrum antibacterial activity and difficult drug resistance generation through simulating the amphiphilic structure of host defensive peptide. And the polypeptide polymer is cheap to synthesize, can be prepared in a large scale, and has great potential in the treatment of microbial infection diseases.

In the face of the stage that microbial resistance is prevalent and antibiotics cannot be completely replaced, there is a need to find a treatment method which can cope with drug-resistant bacteria infection, improve the antibacterial efficiency of antibiotics and is not easy to induce microorganisms to generate drug resistance.

Disclosure of Invention

The invention aims to provide an antibacterial composition, which improves the antibacterial efficiency of antibiotics, is suitable for drug-resistant bacteria infection and is not easy to induce bacteria and fungi to generate drug resistance.

In a first aspect of the present invention, there is provided an antimicrobial composition comprising:

(i) A polypeptide polymer or salt thereof; and

(ii) Antibiotics or medicinal plant extracts.

In another preferred embodiment, the polypeptide polymer consists of one or more repeat units of formula I, the total number of repeat units being a positive integer from 5 to 5000;

wherein m is 0 or 1;

R _a 、R _b 、R _c 、R _d 、R _e each independently selected from: H. amino, C1-C8 alkyl, C6-C10 aryl, - (C1-C8 alkylene) R _f ，R _f Is amino, guanidino, halogen or amideC6-C10 aryl, 5-15 membered heteroaryl, 3-12 membered heterocyclyl, -O-Ra ', -COO-Ra ', -CO-Ra ', -OCO-Ra ' or-S-Ra '; ra' is H, C C8 alkyl, C3C 10 cycloalkyl, C6C 10 aryl, - (C1C 8 alkylene) (C6C 10 aryl); or alternatively

R _c 、R _d Forming a 3-10 membered carbocyclic ring with the attached carbon; r is R _b 、R _c Forms a 3-10 membered carbocyclic ring with the attached carbon.

In another preferred embodiment, the total number of repeating units is a positive integer from 5 to 1000, from 5 to 500, from 5 to 100 or from 5 to 50.

In another preferred embodiment, the polypeptide polymer is an alpha-polypeptide polymer or a beta-polypeptide polymer;

in another preferred example, the salt of the polypeptide polymer is hydrochloride, bromate, trifluoroacetate, phosphate, lithium salt, sodium salt, potassium salt.

In another preferred embodiment, the polypeptide polymer is a homopolymer, a copolymer or a multipolymer consisting of the following A, A ', B, B', C, C ', C ", D, D' structures, the total number of repeating units being a positive integer from 5 to 5000:

wherein r is each independently at the

occurrence

0, 1, 2, 3, 4 or 5;

r' are each independently at the

occurrence

0, 1, 2 or 3;

R ₁ 、R ₂ 、R ₃ each occurrence is independently H, C1-C8 alkyl, amino, C6-C10 aryl, - (C1-C8 alkylene) R _f ，R _f Is amino, guanidino, halogen, amide, C6-C10 aryl, 5-15 membered heteroaryl, 3-12 membered heterocyclyl, -O-Ra ', -COO-Ra ', -CO-Ra ', -OCO-Ra ' or-S-Ra '; ra' is H, C C8 alkyl, C3C 10 cycloalkyl, C6C 10 aryl, - (C1C 8 alkylene) (C6C 10 aryl).

In another preferred embodiment, the polypeptide polymer is selected from the group consisting of:

wherein n is a positive integer of 5 to 5000;

x is more than or equal to 0% and less than or equal to 100%, y is more than or equal to 0% and less than or equal to 100%, and x+y=100%.

In another preferred embodiment, the amino acid in the above structural unit is in the L-configuration, the D-configuration, or a mixture of the D-configuration and the L-configuration.

In another preferred embodiment, the anions of the above structure are selected from the group consisting of: cl ^- 、Br ^- 、CF ₃ COO ^- 、H ₂ PO ₄ ^- 、HPO ₄ ^2- 、PO ₄ ^3- 。

In another preferred embodiment, n is 5 to 100, preferably 5 to 50.

In another preferred embodiment, x: y is 0.01:0.99 to 0.99:0.01, preferably 0.05:0.95 to 0.95:0.05, even 1:9 to 9:1.

wherein each n is independently a positive integer of 5 to 5000, 5 to 1000, 5 to 100 or 5 to 50, 5 to 30 or 10 to 25.

In another preferred example, the antibiotic is any one of a polypeptide antibiotic, an aminoglycoside antibiotic, and a macrolide antibiotic.

In another preferred example, the polypeptide antibiotics are one or a combination of more than two of vancomycin, polymyxin B, polymyxin E, norvancomycin, teicoplanin and derivatives thereof.

In another preferred example, the aminoglycoside antibiotic is one or a combination of more than two of neomycin, streptomycin, gentamicin, kanamycin, amikacin, netilmicin, doxorubicin, tobramycin and derivatives thereof.

In another preferred embodiment, the macrolide antibiotic is clarithromycin, erythromycin, azithromycin, roxithromycin, telithromycin, white mycin, erythromycin, dirithromycin, erythromycin and a combination of two or more of their derivatives.

In another preferred example, the antibiotic is penicillin G, ampicillin, amoxicillin, novobiocin, clarithromycin, fusidic acid, erythromycin, chloramphenicol, azithromycin, rifampin, rifapentine, vancomycin, rifabutin, enrofloxacin, sulfamethazine, and linezolid, and a combination of one or more of their derivatives.

In another preferred embodiment, the antibiotic is selected from the group consisting of: rifampin, enrofloxacin, sulfamethazine, novobiocin, clarithromycin, fusidic acid, erythromycin, chloramphenicol, azithromycin, ampicillin, linezolid, and vancomycin.

In another preferred example, the antibiotic is amphotericin B, fluconazole, voriconazole, itraconazole, caspofungin, micafungin, naftifine, terbinafine, and butenafine, and a combination of one or more of their derivatives, which are resistant to fungal infection.

In another preferred example, the medicinal plant extract is curcumin or a derivative thereof, or other plant extract.

In a second aspect of the present invention there is provided the use of an antimicrobial composition according to the first aspect for the manufacture of a medicament for the prophylaxis and/or treatment of bacterial and/or fungal infection diseases.

In another preferred embodiment, the bacterial infection is an infection with a bacterium selected from the group consisting of: any one of staphylococcus aureus, staphylococcus epidermidis, enterococcus faecium, enterococcus faecalis, bacillus subtilis, escherichia coli, pseudomonas aeruginosa, acinetobacter baumannii, klebsiella pneumoniae, salmonella, vibrio anguillarum, vibrio alginolyticus, vibrio parahaemolyticus, vibrio cholerae, pseudomonas fluorescens, streptococcus agalactiae, vibrio fludrographis and aeromonas hydrophila.

In another preferred embodiment, the fungal infection is an infection with a fungus selected from the group consisting of: candida albicans and cryptococcus neoformans.

In another preferred embodiment, the staphylococcus aureus is methicillin-resistant staphylococcus aureus (MRSA USA 300).

In another preferred embodiment, the salmonella is salmonella pullorum.

In another preferred embodiment, the bacterial infection is caused by infection with methicillin-resistant staphylococcus aureus (MRSA USA 300), escherichia coli (Escherichia coli ATCC 25922), acinetobacter baumannii (Acinetobacter baumannii ATCC BAA 747), vibrio cholerae, vibrio fluvialis, streptococcus agalactiae, salmonella pullorum, enterococcus faecium (Enterococcus faecium 0610), klebsiella pneumoniae (Klebsiella pneumonia NCTC 13440), (Klebsiella pneumonia 0901), pseudomonas aeruginosa (Pseudomonas aeruginosa ATCC27853; pseudomonas aeruginosa 1904).

In a third aspect of the invention there is provided a method of inhibiting bacteria and/or fungi in vitro comprising administering to a subject in need thereof an antimicrobial composition according to the first aspect.

It is understood that within the scope of the present invention, the above-described technical features of the present invention and technical features specifically described below (e.g., in the examples) may be combined with each other to constitute new or preferred technical solutions. Each feature disclosed in the description may be replaced by alternative features serving the same, equivalent or similar purpose. And are limited to a space, and are not described in detail herein.

Drawings

FIG. 1 is a graph showing the results of a synergistic antimicrobial activity test of a combination of a polypeptide polymer and rifampicin against six ESKAPE pathogens.

FIG. 2 is a graph showing the results of MIC tests for a polypeptide polymer in combination with rifampicin to reduce antibiotic resistance in clinical multidrug resistant bacteria. Wherein a is a drug sensitivity test result graph of clinical multi-drug resistant bacteria; b is a graph of MIC comparison results of rifampicin monotherapy in combination with polypeptide polymer and rifampicin against clinically multiple resistant bacteria.

FIG. 3 is a graph showing the results of a test for reducing the amount of antibiotic used in E.coli (Escherichia coli ATCC 25922) using a combination of a polypeptide polymer and a plurality of different antibiotics.

FIG. 4 is a graph showing the results of a bactericidal kinetics study of a combination of a polypeptide polymer and rifampicin against E.coli (Escherichia coli ATCC 25922).

FIG. 5 is a graph showing the results of drug resistance testing of polypeptide polymers.

FIG. 6 is a graph showing the results of a peritonitis survival test in mice treated with a combination of polypeptide polymer and rifampicin for four classes of gram negative bacterial infections in ESKAPE.

FIG. 7 is a graph showing the results of an in vivo antimicrobial test of a combination of a polypeptide polymer and rifampicin in E.coli (Escherichia coli ATCC 25922) infected mice peritonitis.

FIG. 8 is a graph showing the results of an in vivo antimicrobial test of a combination of polypeptide polymer and rifampicin in a peritonitis in a mouse infected with Acinetobacter baumannii (Acinetobacter baumannii ATCC BAA 747).

FIG. 9 is a graph showing the results of an in vivo antimicrobial test of a combination of a polypeptide polymer and rifampicin in Klebsiella pneumoniae (Klebsiella pneumonia 0901) infected mice peritonitis.

FIG. 10 is a graph showing the results of an in vivo antimicrobial test of a combination of a polypeptide polymer and rifampicin in P.aeruginosa (Pseudomonas aeruginosa 1904) in infected mice peritonitis.

FIG. 11 is a graph showing the results of in vivo toxicity testing of polypeptide polymer and rifampicin combination on mice.

Detailed Description

The inventors of the present application have studied extensively and intensively to develop an antibacterial composition comprising: (i) a polypeptide polymer or salt thereof; and (ii) an antibiotic or a medicinal plant extract. The existence of the polypeptide polymer can greatly reduce the dosage of antibiotics, wherein, the dosage of antibiotics can be reduced by 250 times in part of the compositions, and the antibacterial efficiency of the antibiotics is improved. The composition can expand the antibacterial spectrum of antibiotics, cope with drug-resistant bacterial infection, is not easy to induce bacteria and/or fungi to generate drug resistance, saves the antibacterial activity of the antibiotics to drug-resistant strains, relieves the toxic and side effects of the drugs, can be combined with medicinal plant extracts to promote the overall antibacterial effect, and provides a new choice for the fields of preventing and treating bacterial and/or fungal infectious diseases. On this basis, the present invention has been completed.

Terminology

In the present invention, unless otherwise indicated, terms used have the ordinary meanings known to those skilled in the art.

In the present invention, the halogen is F, cl, br or I.

In the present invention, the term "C ₁ -C ₈ "means having 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms," C ₃ -C ₁₀ "means having 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms, and so on. "5-15 membered" means having 5-15 ring atoms, and so on.

In the present invention, the term "alkyl" means a saturated linear or branched hydrocarbon moiety, e.g., the term "C ₁ -C ₈ Alkyl "refers to a straight or branched chain alkyl group having 1 to 8 carbon atoms and includes, without limitation, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl and the like; ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl are preferred.

The term "alkylene" refers to a straight or branched chain saturated aliphatic group having the indicated number of carbon atoms and linking at least two other groups, i.e. a divalent hydrocarbon group. For example, the linear alkylene group may be- (CH) ₂ ) _s -a divalent group, wherein s is 1, 2, 3, 4, 5, 6, 7 or 8. Representative alkylene groups include, but are not limited to, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, sec-butylene, pentylene, and hexylene.

In the present invention, the term "cycloalkyl" means a saturated cyclic hydrocarbyl moiety, e.g., the term "C ₃ -C ₁₀ Cycloalkyl "refers to a cyclic alkyl group having 3 to 10 carbon atoms in the ring and includes, without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and the like.

In the present invention, the term "heterocyclyl" means a saturated or unsaturated, non-aromatic cyclic group containing at least one (e.g. 1, 2, 3 or 4) ring heteroatom (e.g. N, O or S), such as tetrahydropyridinyl, pyrrolinyl, dihydropyridinyl, dihydrofuranyl, dihydrothienyl, morpholinyl.

In the present invention, the term "aryl" means a hydrocarbyl moiety comprising one or more aromatic rings. For example, the term "C ₆ -C ₁₀ Aryl "refers to an aromatic cyclic group having 6 to 10 carbon atoms, such as phenyl, naphthyl, and the like, which does not contain a heteroatom in the ring.

In the present invention, the term "heteroaryl" means an aromatic cyclic group containing at least one (e.g., 1, 2, 3 or 4) ring heteroatom (e.g., N, O or S), such as furyl, pyrrolyl, thienyl, oxazolyl, imidazolyl, thiazolyl, pyridyl, quinolinyl, isoquinolinyl, indolyl, pyrimidinyl, pyranyl.

The invention will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. The experimental procedures, which do not address the specific conditions in the examples below, are generally carried out under conventional conditions (e.g.those described in Sambrook et al, molecular cloning: A laboratory Manual (New York: cold Spring Harbor Laboratory Press, 1989)) or under conditions recommended by the manufacturer. Percentages and parts are weight percentages and parts unless otherwise indicated.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods and materials described herein are presented for illustrative purposes only.

Example 1: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-L-2, 3-diaminopropionic acid-N-carboxycyclic anhydride and L-leucine-N-carboxycyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

N-epsilon-t-butoxycarbonyl-L-2, 3-diaminopropionic acid-N-carboxyanhydride and L-leucine-N-carboxyanhydride were weighed in a nitrogen-protected glove box and prepared to 0.2M each with dry tetrahydrofuran. 2mL of N-epsilon-t-butoxycarbonyl-L-2, 3-diaminopropionic acid-N-carboxyanhydride and 0.5mL of L-leucine-N-carboxyanhydride were mixed and stirred. Lithium hexamethyldisilazide (LiHMDS) was weighed to prepare a solution (0.2M), 500 μl was quickly added to the solution, and the polymerization was confirmed to be completed within 5 minutes by spotting. The polymer was taken out of the glove box, and a white flocculent precipitate was separated out after adding ice petroleum ether (45 mL), centrifuged at 4000rpm for 3 minutes, and the supernatant was removed and dissolved in 1mL of tetrahydrofuran followed by petroleum ether precipitation. After repeating this procedure three times, a polymer with protecting groups on the side chain amino groups was obtained and dried overnight in a vacuum dish. The molecular weight mn=4000, the molecular weight distribution pdi=1.15 of the polymer was identified by Gel Permeation Chromatography (GPC). To the polymer with protecting groups was added 1.5mL of trifluoroacetic acid (TFA) and shaken for 2 hours to deprotect the protecting groups, and after most of the trifluoroacetic acid was blown off, ice methyl t-butyl ether (50 mL) was added and after white precipitate precipitated, collected by centrifugation. Then, the mixture was dissolved in methanol (1 mL), and ice methyl t-butyl ether (50 mL) was precipitated, and after three times of this cycle, the remaining solvent was pumped down with an oil pump overnight. The sample was dissolved with ultrapure water (3 mL) and lyophilized to obtain the deprotected random alpha-polypeptide polymer.

Example 2: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-L-2, 3-diaminobutyric acid-N-carboxyl cyclic anhydride and L-leucine-N-carboxyl cyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was the same as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 1.25mL of N-. Epsilon. -t-butoxycarbonyl-L-2, 3-diaminobutyric acid-N-carboxycyclic anhydride (0.2M) and 1.25mL of L-leucine-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. The molecular weight mn=4100 of the polymer with pendant Boc protecting groups was determined by GPC and the molecular weight distribution pdi=1.21. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 3: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-L-ornithine-N-carboxyl cyclic anhydride and L-leucine-N-carboxyl cyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 2mL of N-. Epsilon. -t-butoxycarbonyl-L-ornithine-N-carboxycyclic anhydride (0.2M) and 0.5mL of L-leucine-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. GPC determines the molecular weight mn=4600, molecular weight distribution pdi=1.24 of the polymer with pendant Boc protecting groups. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 4: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-L-lysine-N-carboxyl cyclic anhydride and L-leucine-N-carboxyl cyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was the same as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 2mL of N-. Epsilon. -t-butoxycarbonyl-L-lysine-N-carboxycyclic anhydride (0.2M) and 0.5mL of L-leucine-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. GPC determines the molecular weight mn=5200 of the polymer with pendant Boc protecting groups, molecular weight distribution pdi=1.14. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 5: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-D, L-lysine-N-carboxycyclic anhydride and L-glutamic acid-5-benzyl ester-N-carboxycyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was the same as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 1.25mL of N-. Epsilon. -t-butoxycarbonyl-D, L-lysine-N-carboxycyclic anhydride (0.2M) and 1.25mL of L-glutamic acid-5-benzyl ester-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. GPC determines the molecular weight mn=5100 of the polymer with pendant Boc protecting groups, molecular weight distribution pdi=1.23. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 6: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-L-lysine-N-carboxycyclic anhydride and O-t-butyl-L-serine-N-carboxycyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was the same as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 2mL of N-. Epsilon. -t-butoxycarbonyl-L-lysine-N-carboxycyclic anhydride (0.2M) and 0.5mL of O-t-butyl-L-serine-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. GPC determines the molecular weight mn=4200 of the polymer with side chain protecting groups, and the molecular weight distribution pdi=1.14. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 7: preparation of random alpha-polypeptide polymer by initiating N-epsilon-t-butoxycarbonyl-D, L-lysine-N-carboxycyclic anhydride and D, L-norleucine-N-carboxycyclic anhydride with hexamethyldisilazane lithium amide (LiHMDS)

The experimental procedure was the same as in example 1, except that 500. Mu.L of LiHMDS (0.2M) was used to initiate 1.5mL of N-. Epsilon. -t-butoxycarbonyl-D, L-lysine-N-carboxycyclic anhydride (0.2M) and 1mL of D, L-norleucine-N-carboxycyclic anhydride (0.2M), and the reaction was completed within 5 minutes. GPC determines the molecular weight mn=4400 of the polymer with pendant Boc protecting groups, molecular weight distribution pdi=1.22. Finally, the random alpha-polypeptide polymer is obtained after deprotection.

Example 8: preparation of random beta-polypeptide polymer by co-initiating beta-lactam monomer MM and beta-lactam monomer CH by using p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

In a nitrogen-protected glove box, β -lactam monomer MM and β -lactam monomer CH were weighed and each prepared to 0.2M with dry tetrahydrofuran. 1.2mL of the β -lactam monomer MM and 0.8mL of the β -lactam monomer CH were mixed and stirred with a stirrer. Lithium hexamethyldisilazide (0.5M) and p-tert-butylbenzoyl chloride (0.2M) were prepared as initiators, 100. Mu.L of each was rapidly added to the solution, and the polymerization was completed after reacting at room temperature for 4 hours. The polymer was taken out of the glove box, quenched with 1 drop of methanol, and white flocculent precipitate was separated out after adding ice petroleum ether (45 mL), centrifuged at 4000rpm for 3 minutes, and the supernatant was removed and dissolved with 1mL of tetrahydrofuran, followed by further precipitation with ice petroleum ether. After repeating this procedure three times, a polymer with protecting groups on the side chain amino groups was obtained and dried overnight in a vacuum dish. The molecular weight mn=3900, and the molecular weight distribution pdi=1.23 of the polymer were identified by Gel Permeation Chromatography (GPC). To the polymer with protecting groups was added 1.5mL of trifluoroacetic acid (TFA) and shaken for 2 hours to deprotect the protecting groups, and after most of the trifluoroacetic acid was blown off, ice methyl t-butyl ether (50 mL) was added and after white precipitate precipitated, collected by centrifugation. Then, the mixture was dissolved in methanol (1 mL), and ice methyl t-butyl ether (50 mL) was precipitated, and after three times of this cycle, the remaining solvent was pumped down with an oil pump overnight. The sample was dissolved with ultrapure water (3 mL) and lyophilized to obtain a deprotected random β -polypeptide polymer.

Example 9: preparation of random beta-polypeptide polymer by CO-initiating beta-lactam monomer DM and beta-lactam monomer CO by using p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

The experimental procedure is the same as in example 8, except that 1.2mL MM (0.2M) and 0.8mL CH (0.2M) are replaced with 1mL DM (0.2M) and 1mL CO (0.2M). Molecular weight mn=3900, molecular weight distribution pdi=1.2 of the polymer having a protecting group in the side chain was identified by Gel Permeation Chromatography (GPC). Finally, the random beta-polypeptide polymer is obtained after deprotection.

Example 10: preparation of random beta-polypeptide polymer by co-initiating beta-lactam monomer DM and beta-lactam monomer CH by using p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

The experimental procedure is the same as in example 8, except that 1.2mL MM (0.2M) and 0.8mL CH (0.2M) are replaced with 1mL DM (0.2M) and 1mL CH (0.2M). The molecular weight mn=4000 of the polymer having a protecting group in the side chain was identified by Gel Permeation Chromatography (GPC), and the molecular weight distribution pdi=1.21. Finally, the random beta-polypeptide polymer is obtained after deprotection.

Example 11: preparation of random beta-polypeptide polymer by co-initiating beta-lactam monomer NM and beta-lactam monomer CP by p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

The experimental procedure is the same as in example 8, except that 1.2mL MM (0.2M) and 0.8mL CH (0.2M) are replaced with 1mL NM (0.2M) and 1mL CP (0.2M). The molecular weight mn=3700 of the polymer with a protecting group in the side chain was identified by Gel Permeation Chromatography (GPC), and the molecular weight distribution pdi=1.22. Finally, the random beta-polypeptide polymer is obtained after deprotection.

Example 12: preparation of random beta-polypeptide polymer by co-initiating beta-lactam monomer MM and beta-lactam monomer CP with p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

The experimental procedure is the same as in example 8, except that 1.2mL MM (0.2M) and 0.8mL CH (0.2M) are replaced with 1mL MM (0.2M) and 1mL CP (0.2M). Molecular weight mn=3800, molecular weight distribution pdi=1.22 of the polymer having a protecting group in the side chain was identified by Gel Permeation Chromatography (GPC). Finally, the random beta-polypeptide polymer is obtained after deprotection.

Example 13: preparation of random beta-polypeptide polymer by co-initiating beta-lactam monomer DAP and beta-lactam monomer CP by p-tert-butylbenzoyl chloride and hexamethyldisilazide lithium salt

The experimental procedure is the same as in example 8, except that 1.2mL MM (0.2M) and 0.8mL CH (0.2M) are replaced with 1mL DAP (0.2M) and 1mL CP (0.2M). The molecular weight mn=3700 of the polymer with a protecting group in the side chain was identified by Gel Permeation Chromatography (GPC), and the molecular weight distribution pdi=1.2. Finally, the random beta-polypeptide polymer is obtained after deprotection.

Example 14: testing of anti-bacterial Activity of polypeptide Polymer

The antimicrobial agent selected was the polypeptide polymer of examples 1-12. The selected test strain comprises methicillin-resistant staphylococcus aureus (MRSA USA 300), escherichia coli (Escherichia coli ATCC 25922) and acinetobacter baumannii (Acinetobacter baumannii ATCC BAA 747). These strains were all from the American Type Culture Collection (ATCC).

The test bacteria were inoculated in liquid LB medium and shaken in a shaker at 37℃and 150rpm for 10h. Centrifuging the cultured bacterial suspension at 4000rpm for 5min, adding MH culture medium, mixing, centrifuging again, and adding enzymeThe concentration of bacterial suspension was diluted to 2X 10 by a standard instrument ⁵ CFU/mL was ready for use. The polymer was prepared with ultrapure water to a solution of 4mg/mL for use. Taking a 96-well plate, obtaining 50 mu L of polymer solution with the final concentration of 1.56-200 mu g/mL by a gradient dilution method, adding 50 mu L of diluted bacterial suspension respectively, and taking MH culture medium as a negative control and taking MH culture medium plus bacterial liquid as a positive control. After slight shaking, the mixture was placed in an incubator at 37℃for cultivation. After 9h, the OD600 was read at 600nm wavelength of the microplate reader, according to the formula "% bacterial growth = (OD) ^Polymer -OD ^{Blank space} )/(OD ^Control -OD ^{Blank space} ) The calculation was performed by x 100%. In MIC testing, there are two replicates per sample, and the test is repeated three times to ensure accuracy of the results.

Table 1 antimicrobial Activity (MIC, μg/mL) of polypeptide polymers

Example 15: haemolytic Activity test of polypeptide Polymer on Red blood cells

Since the antibacterial agent enters the blood circulation of animals when used in vivo, it is necessary to verify its hemolytic activity against red blood cells to prove the safety of the antibacterial agent. The polypeptide polymers of examples 1,5-8, 11 and 12 were selected for hemolytic activity testing of human red blood cells. Fresh blood drawn from volunteers was kept in a refrigerator at 4℃until use, an appropriate amount of blood was taken out at the time of test, and after adding triethanolamine-buffered saline (TBS) and gently shaking, it was centrifuged at 4000rpm for 3min, and after pouring out the supernatant, it was added with TBS and shaking, and centrifugation was repeated three times. The red blood cells were diluted to 5% by adding an appropriate amount of TBS. The test antibiotic was subjected to gradient dilution with TBS as negative control and 0.1% polyethylene glycol octyl phenyl ether as positive control in 96-well plates according to the procedure of example 5, after which 50. Mu.L of diluted red blood cells were added to each well at 37 Culturing at the temperature of 1h. The 96-well plates were centrifuged at 3700rpm for 5min in a centrifuge, 80 μl of supernatant was aspirated from each well into another 96-well plate, and the reading was performed on a microplate reader at a wavelength of 405 nm. Finally according to the formula%hemolysis = (OD ^Polymer -OD ^{Blank space} )/(OD ^Control -OD ^{Blank space} ) X 100% calculation, there were two replicates for each sample in the hemolytic activity test, and three replicates were performed. The hemolytic activity of this test was measured at a fifty percent hemolysis rate (HC ₅₀ ) The results are shown in Table 2, HC for the polypeptide polymer tested ₅₀ All greater than 200. Mu.g/mL, no significant hemolytic activity occurs in the range of use.

TABLE 2 haemolytic Activity of polypeptide polymers (HC ₅₀ ，μg/mL)

Example 16: cytotoxicity test of polypeptide polymers on mammalian cells

The antibacterial agent is used in vivo in contact with other cells, and thus cytotoxicity to mammalian cells is tested to verify in vivo safety. The polypeptide polymers of examples 1,5-8, 11 and 12 were selected for MTT cytotoxicity assays on African monkey kidney cells COS 7. Cells were first cultured at 37 ℃, digested with trypsin when grown to the appropriate density, seeded with 5000 cells in each well of a 96-well plate, and incubated overnight in an incubator at 37 ℃,5% co2 concentration. The next day in a new 96-well plate, the polypeptide polymer or the antibacterial agent to be tested is subjected to gradient dilution by using a culture medium, the culture medium in the cell-well plate is sucked out, and then the diluted solution is transferred into the cell-well plate line by line and cultured overnight at 37 ℃. After 24 hours, the medium in the well plate was aspirated, 100. Mu.L of thiazole blue dye (MTT, 0.5 mg/mL) was added, and the mixture was placed in an incubator to be cultured for 4 hours for staining. The MTT dye was then carefully aspirated away, 150. Mu.L of dimethyl sulfoxide (DMSO) was added and placed in 200rpm and shaken for 15min to fully dissolve the purple crystals. The well plate was read at 570nm wavelength in an microplate reader and cell viability was calculated according to the formula ％＝(OD ^Polymer -OD ^{Blank space} )/(OD ^Control -OD ^{Blank space} ) The calculation was performed by x 100%. Three replicates were performed for each sample in the MTT test and three replicates were performed. Cytotoxicity results at fifty percent cell survival (IC ₅₀ ) And displaying. The test results are shown in Table 3, which shows the IC of the polypeptide polymer ₅₀ All greater than or equal to 175. Mu.g/mL, indicating that it has no significant cytotoxicity to mammalian cells.

TABLE 3 cytotoxicity of polypeptide polymers (IC ₅₀ ，μg/mL)

Example 17: synergistic antibacterial Activity test of polypeptide Polymer and Rifampicin combination against Acinetobacter baumannii (Acinetobacter baumannii BAA 747)

The polypeptide polymer of examples 1-12 was selected and the antibiotic was rifampicin, and the synergistic effect of both was evaluated using the Fractional Inhibitory Concentration Index (FICI) as an indicator. After Acinetobacter baumannii was cultured in the same manner as in example 13, the bacterial suspension was diluted to a concentration of 5X 10 by using a microplate reader ⁵ CFU/mL was ready for use. In two 96-well plates, the polymer was diluted in longitudinal gradients as in example 12, the final row being pure MH medium and each well being finally 40. Mu.L. A new 96-well plate was taken, 25. Mu.L of rifampicin solution was added to the first column and diluted with MH in a lateral gradient, the tenth column was pure MH medium, and finally 100. Mu.L of each well was obtained. Respectively, 40. Mu.L of the bacterial suspension was pipetted from each well into the corresponding well of the polymer well plate and 20. Mu.L of the bacterial suspension was added to each well, the final liquid volume in each well was 100. Mu.L, and the final bacterial concentration was 10 ⁵ CFU/mL, where MH medium was used as negative control, MH medium plus bacterial liquid was used as positive control. The plates were incubated and read as described in example 13 to obtain MIC values for the antibiotic, the polymer, and both. FICI is according to the formula fici= (MIC _{Polymer combination} /MIC _{Polymer for single use} )+(MIC _{Antibiotic combinations} /MIC _{Antibiotic single use} ) And (5) performing calculation. When FICI is less than or equal to 0.5, the synergistic antibacterial effect between the two can be considered. The experimental results are shown in table 4. All polypeptide polymers tested and the antibiotic rifampicin produced a significant synergistic antibacterial effect.

TABLE 4 synergistic effects of polypeptide polymers and rifampicin combination on Acinetobacter baumannii

Example 18: synergistic antibacterial activity test of polypeptide polymer and curcumin combination

The synergistic antibacterial activity of the composition was tested against Vibrio cholerae, vibrio fluvialis and Vibrio alginolyticus using the combination of the polypeptide polymer of example 6 and curcumin as in example 17. The experimental results are shown in table 5. The combination of the tested polypeptide polymer and curcumin can produce obvious synergistic antibacterial effect.

Table 5 synergistic antimicrobial activity test of polypeptide polymers and curcumin in combination

Example 19: synergistic antibacterial effect of polypeptide polymer and sulfamethoxazole on salmonella pullorum

The synergistic antimicrobial activity of the composition was tested against Salmonella pullorum using the combination of the polypeptide polymer of example 4 and sulfamethoxydiazine, the strain purchased from China center for type culture collection (CVCC), and tested as in example 17. The experimental results are shown in table 6. The combination of the tested polypeptide polymer and the sulfamethazine can generate obvious synergistic antibacterial effect on salmonella pullorum, and the dosage of the antibiotic sulfamethazine is reduced.

Table 6 synergistic effects of polypeptide polymers and Sulfamethoxypyrimidine combinations on Salmonella pullorum

Example 20: synergistic antifungal effects of polypeptide polymer and antifungal drug combination on drug-resistant candida albicans

The synergistic antifungal activity of different compositions against drug resistant candida albicans K1 was tested using the polypeptide polymer of example 13 in combination with the antifungal drug fluconazole or itraconazole or caspofungin as in example 17. Except that the medium was changed from MH to RPMI, the test strain was changed to Candida albicans K1, and the final fungal concentration was 1250CFU/mL. The experimental results are shown in table 7. The tested polypeptide polymer and antifungal agent itraconazole or caspofungin can generate obvious synergistic antibacterial effect on drug-resistant candida albicans K1, and when the polypeptide polymer and fluconazole are combined, the dosage of fluconazole can be greatly reduced when the concentration of the polypeptide polymer is 1/2 MIC.

Table 7 synergistic antifungal Effect of polypeptide Polymer and antifungal drug combinations on drug-resistant Candida albicans K1

Example 21: synergistic antibacterial Activity test of polypeptide Polymer and Rifampicin combination against six pathogenic bacteria of ESKAPE

The synergistic effect of the antibacterial composition on ESKAPE six pathogenic bacteria enterococcus faecium (Enterococcus faecium 0610), methicillin-resistant staphylococcus aureus (MRSA USA 300), klebsiella pneumoniae (Klebsiella pneumonia NCTC 13440), escherichia coli (Escherichia coli ATCC 25922), acinetobacter baumannii (Acinetobacter baumannii ATCC BAA 747) and pseudomonas aeruginosa (Pseudomonas aeruginosa ATCC 27853) was tested by selecting the polypeptide polymer of example 1 in combination with rifampicin. The strains used were isolated from the American Type Culture Collection (ATCC), the British classical collection (NCTC) and the Hospital clinic, respectively. Synergistic antimicrobial testing was performed as in example 17. As shown in FIG. 1, the polypeptide polymer and rifampicin combination has synergistic antibacterial effect on six pathogenic bacteria of ESKAPE.

Example 22: combination of polypeptide Polymer and Rifampicin the combination of polypeptide Polymer and Rifampicin of example 1 was used to reduce the amount of antibiotic used in clinical multidrug resistance, and the antibacterial composition was tested for the synergistic effect of the composition on clinical multidrug resistance E.coli isolated in hospitals (Escherichia coli), acinetobacter baumannii (Acinetobacter baumannii), pseudomonas aeruginosa (Pseudomonas aeruginosa) and Klebsiella pneumoniae (Klebsiella pneumoniae). Clinical strains isolated in hospitals were found to be resistant to a variety of different types of antibiotics by drug susceptibility testing (fig. 2 a). The synergistic antibacterial test was performed according to the method of example 17, and the experimental results are shown in fig. 2 b, wherein the polypeptide polymer can reverse the drug resistance of multi-drug resistant bacteria to rifampicin, and the use amount of antibiotics is greatly reduced. Wherein the amount of rifampicin used in Pseudomonas aeruginosa 0907 can be reduced 250-fold after the combination of polypeptide polymer and rifampicin.

Example 23: the combination of polypeptide polymer and several different antibiotics reduces the amount of antibiotic used in coliform bacteria (Escherichia coli ATCC, 25922)

The polypeptide polymer of example 1 was selected, and the selected antibiotics were rifampin, neomycin, clarithromycin, fusidic acid, erythromycin, chloramphenicol, azithromycin, ampicillin, linezolid, and vancomycin. The experimental procedure is as in example 17. The experimental results are shown in fig. 3, the polypeptide polymer can generate synergistic antibacterial effect with all the antibiotics tested, inhibit the growth of quality control bacteria Escherichia coli ATCC and 25922, and greatly reduce the dosage of the antibiotics. Wherein the polypeptide polymer and the rifampicin have the strongest synergistic effect, and the amount of the rifampicin can be reduced by more than 32 times.

Example 24: sterilization kinetics study of E.coli (Escherichia coli ATCC 25922) with polypeptide Polymer in combination with Rifampicin

The polypeptide polymer of example 1 was selectedAnd the commercial antibiotic rifampicin as an antibacterial composition, the kinetics of sterilization was studied. Coli (Escherichia coli ATCC 25922) was cultured to a growth phase as in example 14, diluted to 2X 10 with medium ⁵ CFU/mL was ready for use. Equal volumes of the compositions of example 1 (final concentration 1/4 MIC) and rifampicin (final concentration 1/4 MIC), example 1 (final concentration 1/4 MIC) and rifampicin (final concentration 1/4 MIC) were then added, respectively. The mixture was placed in a 37 degree incubator and 10 μl of the bacterial fluid was removed at various time intervals to dilute the coated plates, and the sterilization kinetics of the antimicrobial composition, which completely killed Escherichia coli ATCC25922 within 6 hours, was finally determined as shown in fig. 4, whereas the polypeptide polymer and rifampin alone did not inhibit bacterial growth.

Example 25: drug resistance test of polypeptide polymers

The polypeptide polymer, polypeptide polymer and antibiotic rifampicin combination of example 1 and the last line of defense polymyxin E of gram-negative bacteria were selected to continuously stimulate E.coli (Escherichia coli ATCC 25922), respectively, the gram-negative bacteria. After the bacteria to be tested have been cultivated as in example 14, they are diluted to OD with MH ₆₀₀ =1, 2.5 μl of bacterial liquid was taken into 1mL of MH medium, added with the antimicrobial agent to give a final concentration of 1/2MIC, and incubated at 37 ℃ for 24h. This operation was repeated daily, and the MIC of each generation of bacteria was tested, and the concentration of the antibacterial agent was appropriately adjusted according to the MIC value. The final MIC values were tested after a total of 20 days of antimicrobial stimulation, repeated with four days as a cycle, to determine the increase in bacterial resistance. MIC results (fig. 5) indicate that the respective MIC did not significantly increase after 24 days of continuous stimulation of escherichia coli with the polypeptide polymer and the antimicrobial composition; the MIC of the bacteria continuously stimulated by the antibiotic polymyxin E is increased by 64 times, which proves that the use of the polypeptide polymer alone and the combination of the polypeptide polymer and the antibiotic are not easy to promote the bacteria to generate drug resistance.

Example 26: peptide Polymer and Rifampicin combination treatment of mice infected with four classes of gram-negative bacteria in ESKAPE survival experiments

In the mouse peritonitis infection survival experiments, ICR female mice (six weeks, 22±1 g) were randomly caged, 6 animals per group, the polymer was polypeptide polymer P2 in example 1, the antibiotic was rifampicin Rif, and the bacteria tested included klebsiella pneumoniae (Klebsiella pneumonia 0901), escherichia coli (Escherichia coli ATCC 25922), acinetobacter baumannii (Acinetobacter baumannii ATCC BAA 747) and pseudomonas aeruginosa (Pseudomonas aeruginosa 1904). The mice were intraperitoneally injected with a lethal bacterial solution (diluted with 5% mucin in physiological Saline) and 1h later with the polypeptide polymer (P2), the antibiotic rifampicin (Rif), the antimicrobial composition of the polypeptide polymer and rifampicin (p2+rif) and physiological Saline (Saline) of example 4, respectively, for treatment (wherein Klebsiella pneumonia 0901 infection groups were administered for treatment 1 hour and 6 hours later, respectively). The mice were observed for life status over 7 days and their survival was recorded. The experimental results show that the survival rate of mice treated by the antibacterial composition P2+Rif is significantly higher than that of other groups, and the combination of the polypeptide polymer and the antibiotics has excellent treatment effect in vivo (figure 6).

Example 27: polypeptide Polymer and Rifampicin in vivo antibacterial test in the peritonitis of Escherichia coli ATCC25922 infected mice

The treatment was performed by intraperitoneally injecting a lethal Escherichia coli ATCC25922 strain solution in ICR mice according to the method of example 26, and 1h later injecting the polypeptide polymer P2 (30 mg/kg), the antibiotic rifampicin Rif (5 mg/kg), the polypeptide polymer and the antibacterial composition of rifampicin P2+Rif (30 mg/kg+5 mg/kg) and physiological Saline (Saline) of example 1, respectively. The mice were dissected 12h after infection, heart, liver, spleen, lung, kidney, blood and peritoneal lavage fluid were collected, homogenized and diluted and plated. Experimental results show that the combination of the polypeptide polymer and the antibiotics can significantly reduce the bacterial number in organs, and effectively treat the peritonitis of Escherichia coli ATCC25922 infected mice (figure 7).

Example 28: polypeptide Polymer and Rifampicin in vivo antibacterial test in Acinetobacter baumannii ATCC BAA747 infected mice peritonitis

Experimental procedure the procedure is as in example 27, except that the bacterium is replaced with Acinetobacter baumannii ATCC BAA747 and the concentration of administration is replaced with the polypeptide polymer P2 (20 mg/kg), the antibiotic rifampicin Rif (0.5 mg/kg), the polypeptide polymer and the antibacterial composition of rifampicin P2+Rif (20 mg/kg+0.5 mg/kg) of example 1. Experimental results show that the combination of the polypeptide polymer and the antibiotics can significantly reduce the bacterial number in organs, and effectively treat the peritonitis of Acinetobacter baumannii ATCC BAA747 infected mice (figure 8).

Example 29: polypeptide Polymer and Rifampicin in vivo antibacterial test in mice peritonitis infected with Klebsiella pneumonia 0901

Experimental procedure the procedure is as in example 27, except that the bacteria are replaced with Klebsiella pneumonia 0901 and the concentration of administration is replaced with the polypeptide polymer P2 (25 mg/kg), the antibiotic rifampicin Rif (5 mg/kg), the polypeptide polymer and the antibacterial composition of rifampicin P2+Rif (25 mg/kg+5 mg/kg) of example 1, and administered 1 hour and 6 hours after infection, respectively. Experimental results show that the combination of the polypeptide polymer and the antibiotics can significantly reduce the bacterial number in organs, and effectively treat the peritonitis of Klebsiella pneumonia 0901-infected mice (figure 9).

Example 30: polypeptide Polymer and Rifampicin in vivo antibacterial test in Pseudomonas aeruginosa 1904 infected mice peritonitis

The experimental procedure was as in example 27, except that the bacteria were replaced with Pseudomonas aeruginosa 1904 and the concentration administered was as in example 27. Experimental results show that the combination of the polypeptide polymer and the antibiotics can significantly reduce the bacterial count in organs, and effectively treat the peritonitis of Pseudomonas aeruginosa 1904 infected mice (figure 10).

Example 31: in vivo toxicity test of polypeptide Polymer and Rifampicin combination on mice

Healthy ICR mice (six weeks, 22±1 g) were randomly caged, 6 animals per group, the polypeptide polymer selected was polypeptide polymer P2 of example 1, the antibiotic was rifampicin Rif, and physiological saline was used as a blank. The dose of the antibacterial composition (polypeptide polymer p2+rifampin rif=30 mg/kg+5 mg/kg) capable of curing peritonitis of mice was selected, blood was collected by heart blood collection after 2 days and 7 days of intraperitoneal injection of the antibacterial composition into mice, serum was obtained by centrifugation and analyzed by serum biochemical detection instrument (fig. 11), and at this dose neither the polypeptide polymer nor rifampin had an effect on liver, kidney and in vivo salt content of mice, indicating that the combination of polypeptide polymer and rifampin had no significant in vivo toxicity.

All documents mentioned in this application are incorporated by reference as if each were individually incorporated by reference. Further, it will be appreciated that various changes and modifications may be made by those skilled in the art after reading the above teachings, and such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. An antimicrobial composition, wherein the antimicrobial composition comprises:

(i) A polypeptide polymer or salt thereof; and

(ii) Antibiotics or medicinal plant extracts.

2. The antimicrobial composition of claim 1, wherein the polypeptide polymer consists of one or more repeat units of formula i, the total number of repeat units being a positive integer from 5 to 5000;

wherein m is 0 or 1;

R _a 、R _b 、R _c 、R _d 、R _e each independently selected from: H. C1-C8 alkyl, amino, C6-C10 aryl, - (C1-C8 alkylene) R _f ，R _f Is amino, guanidino, halogen, amide, C6-C10 aryl, 5-15 membered heteroaryl, 3-12 membered heterocyclyl, -O-Ra ', -COO-Ra ', -CO-Ra ', -OCO-Ra ' or-S-Ra '; ra' is H, C C8 alkyl, C3C 10 cycloalkyl, C6C 10 aryl, - (C1C 8 alkylene) (C6C 10 aryl); or alternatively

R _c 、R _d Forming 3-10 membered carbon with the attached carbonA ring; r is R _b 、R _c Forms a 3-10 membered carbocyclic ring with the attached carbon.

3. The antimicrobial composition of claim 1, wherein the polypeptide polymer is a homopolymer, a copolymer or a multipolymer consisting of the following A, A ', B, B', C, C ', C ", D, D' structures, the total number of repeating units being a positive integer from 5 to 5000:

wherein r is each independently at the occurrence 0, 1, 2, 3, 4 or 5;

r' are each independently at the occurrence 0, 1, 2 or 3;

4. The antimicrobial composition of claim 1, wherein the polypeptide polymer is selected from the group consisting of:

wherein n is a positive integer of 5 to 5000;

5. The antimicrobial composition of claim 1, wherein the antibiotic is any one of a polypeptide antibiotic, an aminoglycoside antibiotic, and a macrolide antibiotic that is resistant to bacterial infection.

6. The antimicrobial composition of claim 5, wherein the polypeptide antibiotic is one or a combination of more than two of vancomycin, polymyxin B, polymyxin E, norvancomycin, teicoplanin, and derivatives thereof;

the aminoglycoside antibiotics are one or more than two of neomycin, streptomycin, gentamicin, kanamycin, amikacin, netilmicin, doxorubicine, tobramycin and derivatives thereof;

The macrolide antibiotics are one or more than two of clarithromycin, erythromycin, azithromycin, roxithromycin, telithromycin, white mycin, erythromycin estolate, dirithromycin, erythromycin fluoride and derivatives thereof.

7. The antimicrobial composition of claim 1, wherein the antibiotic is penicillin G, ampicillin, amoxicillin, novobiocin, clarithromycin, fusidic acid, erythromycin, chloramphenicol, azithromycin, rifampin, rifapentine, vancomycin, rifabutin, enrofloxacin, sulfamethoxazole, and linezolid, and a combination of one or more thereof.

8. The antimicrobial composition of claim 1, wherein the antibiotic is amphotericin B, fluconazole, voriconazole, itraconazole, 5-fluorocytosine, nikkomycin, caspofungin, micafungin, naftifine, terbinafine, and butenafine, and combinations of one or more of their derivatives, which are resistant to fungal infections.

9. The antimicrobial composition of claim 1, wherein the medicinal plant extract is curcumin or a derivative thereof, or other plant extract.

10. Use of an antibacterial composition according to claim 1, for the preparation of a medicament for the prevention and/or treatment of bacterial and/or fungal infection diseases.