AU2402599A - Synergistic detergent and disinfectant combinations for decontaminating bio film-coated surfaces - Google Patents

Description

18/06 '99 FRI 15:27 FAX 61 02 62853593 I.P AUSTRALIA 006 1

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: UNIVERSITE DE MONTREAL Actual Inventors: Andr6 PREVOST, Jean Ludger COTE, Robert Esther FAUCHER

BARBEAU,

CHARLAND,

Address for Service: Invention Title: CULLEN CO., Patent Trade Mark Attorneys,.

240 Queen Street, Brisbane, Qld. 4000, Australia.

SYNERGISTIC DETERGENT AND DISINFECTANT COMBINATIONS FOR DECONTAMINATING BIOFILM-COATED

SURFACES

Nos.

The following statement is a full description of this invention, including the best method of performing it known to us 18 JUN '99 15:28 61 02 62853593 PAGE. 006 18 JU 991:8 10 68353 PG 0 18/06 '99 FRI 15:27 FAX 61 02 62853593 I.P AUSTRALIA la This invention has been divided from the specification of Australian patent application no.

42957/96.

BACKGROUND OF THE INVENTION 1. Field of the invention: The present invention relates to novel synergistic detergent and disinfectant combinations and to an improved method for effectively decontaminating biofilm-coated surfaces. Types of surfaces comprise: the inner surface of aqueous liquid-supplying lines, particularly fresh water lines such as those supplying water to dental instruments regularly used by dentists, dental surgeons or dental hygienists, the inner surface of lines of larger diameters and the inner surface of containers having received aqueous liquids for a sufficient length of time to have allowed growth of microorganisms, their deposition and their organization as a biofilm to adhere to the walls of the containers. More particularly, the present invention relates to detergent-disinfectant combinations for dislodging biofilm formed or accumulated on contaminated surfaces for destroying the microorganisms contained therein.

The preferred compositions are particularly suitable for water pipes of dental instruments which are of a small diameter, because no scrubbing is needed for maximal efficiency in a convenient time of decontamination.

2. Brief description of the prior art: Dentists, dental surgeons and dental hygienists and their patients are well aware of the importance of meticulously sterilizing and disinfecting dental instruments. Indeed, since dental 007 18 JUN '99 15:29 61 02 62853593 PAGE. 007 18 J N '9 15 29 6 02 6285 593 PAGE 00 18/06 '99 FRI 15:27 FAX 61 02 62853593 I.P AUSTRALIA 10008 2 instruments are used directly in a patient's mouth, when bleeding may sometimes occur as a result of a dental procedure, it is of paramount importance to minimize the presence of microorganisms carried by dental instruments. The microorganisms can of course range from relatively harmless bacteria to dangerous pathogens. Consequently, efforts are deployed to remove microorganisms from dental instruments and from the fresh water lines feeding dental instruments such as air/water guns, high speed water turbines or ultrasonic tartar removers. For most hand held dental instruments, thermal sterilization remains one of the best methods for eradicating the presence of microorganisms. However, thermal sterilization is obviously not practical for the decontaminating of fresh water lines which remain to this date difficult to rid of microorganisms.

It is well known in the dental profession that small diameter pipes carrying fresh water are contaminated by bacteria and other microorganisms contained in the water flowing through them. Some of the microorganisms inevitably adhere to the inner walls of the pipes and accumulate together with microscopic sediments or other substances into what is commonly known as a biofilm. The biofilm quickly and tenaciously coats the inner walls of the pipes. The biofilm becomes a culture medium for more microorganisms. For example bacteria population will rapidly reach alarming levels which will also be found in the water discharge from the dental instruments connected to the fresh water line. For example, the average bacteria count in the water discharge of dental instruments is known to be of approximately 200,000 colony forming units per milliliter (cfu/ml) and in some extreme cases can reach 10,000,000 cfu/ml.

18 JUN '99 15:29 61 02 62853593 PAGE. 008 18 JUN '99 15:29 61 02 62853593 PAGE. 008 18/06 '99 FRI 15:28 FAX 61 02 62853593 I.P AUSTRALIA z 009 3 It has been suggested to use sterile water, to drain the fresh water lines during periods of non-use or to use filters to catch the microorganisms. However, none of those methods have been shown to effectively remedy the microorganism proliferation for any length of time.

It is also known in the art to use disinfectants such as povidone-iodine at a concentration of approximately 10% to reduce the number of microorganisms in small diameter water lines. It is further also known that a mixture of mandelic and lactic acids reduce the number of sensitive microorganisms in contaminated catheters.

However, such disinfection is somewhat superficial since it fails to effectively attack and destroy the microorganisms found in the biofilm. Consequently, the disinfection effect is short-lived. After 24 hours of treatment with povidone-iodine, the number of bacteria is greatly reduced but quickly begin to rise after eight days.

It is also known to use a detergent such as polyoxyethylene sorbitan monooleate (Tween 80 T) at approximately 4% concentration to dislodge biofilm from small diameter water lines used in dental equipment. However, the use of detergent alone does not effectively destroy the microorganism population.

Accordingly there remains a need for a composition for decontaminating small diameter Water lines for dental equipment which will effectively dislodge and eliminate a biofilm and at the same time destroy the microorganism flora in the fresh water and in the dislodged biofilm.

18 JUN '99 15:29 61 02 62853593 PAGE. 009 18 JUN '99 15:29 61 02 62853593 PAGE. 009 18/06 '99 FRI 15:28 FAX 61 02 62853593 I.P AUSTRALIA o010 4 SUMMARY OF THE INVENTION The invention provides a synergistic cleaning and disinfecting composition for use in decontaminating biofilm-coated surfaces like the fresh water lines providing water supply to dental instruments, these lines being susceptible to contamination by microorganisms and being susceptible to the formation of biofilm coatings on their inner walls, the composition comprising an effective amount of a detergent and of a denaturing agent affecting the integrity of the proteins and of mucopolysaccharides composing the biofilm for dislodging biofilm accumulation on the inner walls of the liens and an effective amount of a bactericide for destroying the microorganisms within the weakened biofilm or retrieved in suspension.

According to the invention, the detergent is sodium dodecyl sulfate (SDS). This detergent is the prototype of a class of detergents having denaturant as well as detergent action, so that the addition of a denaturing agent is not necessary. The bactericide is the potent oxidant hydrogen peroxide

(H

2 0 2 the oxidant being combined with the chelating agent ethylenediaminetetraacetate

(EDTA).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Surprisingly, the inventors have found synergistic compositions for decontaminating microorganism-contaminated water lines having a biofilm coating the inner walls thereof which comprises the following combinations of ingredients: 1) A suitable detergent for reducing the surface tension of the biofilm; 2) A denaturing agent for affecting the integrity of the proteins and of the- mucopolysaccharides, which are bacterial cell components or constituents of the extra-cellular matrix (the detergent and denaturing functions are both assigned to the detergent SDS 18 JUN '99 15:30 61 02 62853593 PAGE. 010 18 JN '9 1530 6 026285593PAGE 01 18/06 '99 FRI 15:28 FAX 61 02 62853593 I.P AUSTRALIA @011 which has being successfully tried at a 1 to 2% concentration in distilled water); and 3) A suitable bactericidal component composed of the potent oxidant hydrogen peroxide (H,0 2 The combination denaturing detergent/oxidant needs complementation with the chelating agent like ethylenediaminetetraacetate (EDTA), to achieve maximal efficacy.

A mixture of the following products has been found to be advantageous: SDS 1-2% (w/v) Hydrogen peroxide 5% and EDTA 1% (w/v) The combination of the three compounds listed above is particularly advantageous because it contains bactericides with together attack a wide spectrum of sensitive bacteria. Should a resistant bacterium be discovered in the biofilm, this combination of compounds may be amended to include another effective bactericide or it may be complemented by the adjunction of such another bactericide.

Suitable decontaminant solutions should contain a detergent able to decrease the surface tension of the biofilm, a denaturing ingredient capable of decreasing the cohesive force existing between microorganisms and between the microorganisms and the surfaces, and a bactericide.

A compound like SDS has a dual action as a detergent and as a denaturing ingredient decreasing the cohesive force of components of the biofilm.

SDS is indeed a denaturing detergent which attacks the integrity of proteins and of mucopolysaccharides. Hydrogen peroxide also has a dual action as bactericide and potent oxidant which attacks the extracellular matrix. When the SDS detergent is used in combination with the potent 18 JUN '99 15:30 61 02 62853593 PAGE. 011 18 JUN '99 15:30 61 02 62853593 PAGE. 011 18/06 '99 FRI 15:29 FAX 61 02 62853593 I.P AUSTRALIA U012 6 oxidant hydrogen peroxide, this particular combination needs to be complemented by a chelating agent for maximizing the disintegration of the extracellular matrix. This suggests that the denaturing action of SDS is not sufficient by itself to make the biofilm in a state of sufficient vulnerability for the action of this particular type of bactericide; the chelating agent is necessary in this case.

The synergistic effect of the effective composition of the present invention can perhaps be explained as follows. It is known that microorganisms present in a biofilm are generally much more resistant to bactericides than microorganisms present in an aqueous medium. The biofilm is thought to act as a physical barrier through which disinfectant agents fail to penetrate and kill the microorganisms present therein.

Consequently, in order to eradicate a maximal number of the microorganisms present in small diameter water lines and particularly in the biofilm coating the inner wall of the small diameter water lines, it is important to simultaneously dislodge the biofilm from the inner walls of the lines so that the bactericide can efficiently attack as many microorganisms as possible. In sequence, the denaturing detergent is thought to help the penetration of the bactericide (and the chelating agent when present), dislodge a layer of biofilm which becomes suspended in the small diameter water lines where the bactericide can attack the microorganisms present. This process will expose a lower layer of the biofilm and of living microorganisms which will again be dislodged and killed. The dislodging action of the detergent and of the denaturing agent and the antibacterial action of the bactericide are thus improved.

When the SDS used in the composition 18 JUN '99 15:30 61 02 62853593 PAGE. 012 18 JUN '99 15:30 61 02 62853593 PAGE. 012 18/06 '99 FRI 15:29 FAX 61 02 62853593 I.P AUSTRALIA 10013 7 produces foam, it might be desirable to add an antifoamer. Also, a colorant might be added to the compositions of this invention for easy monitoring of the extent of rinsing.

Fresh water lines supplying dental instruments are of a very small diameter, which excludes the possibility of scrubbing. The compositions of the present invention have the advantage of showing efficient decontamination in the complete absence of scrubbing in a convenient time of decontamination. The present invention is not only useful for dental instruments. It will become obvious that it is intended for other applications, e.g.

decontaminating any types of tubing or containers on the surface of which microorganisms are adsorbed and form a biofilm. In such other applications, scrubbing or any other mechanical aid is not at all excluded.

Should these compositions be used in pipes of a larger diameter and length, for example, wherein a non-cost effective large volume of decontaminating solution would be needed to fill completely these pipes, it is possible that a mechanical action would help in the distribution of the solution. A mechanical aid, when envisaged, can also help in reducing the duration of decontamination. It is further not excluded to add a vehicle allowing the disinfecting solution to stay in contact with the surface to be decontaminated.

It should also be appreciated that more concentrated solutions could be made inasmuch as the components thereof stay in a solubilized state, otherwise some or all of these components might be delivered in separate vials to be admixed in the final IS JUN '99 15:31 61 02 62853593 PAGE. 013 18 JN '9 1531 6 026285593PAGE 01 18/06 '99 FRI 15:30 FAX 61 02 62853593 I.P AUSTRALIA ]014 8 reconstituted volume and proportions of the above effective decontaminating solutions. This could reduce the manutention and storage of large volumes of decontaminating solutions when they are used for disinfecting large surfaces.

EXPERIMENTAL

The synergistic effect of the compositions of the present invention was demonstrated by the following experiment. Four sections of a small diameter (5 mm) water line, contaminated with a relatively thick biofilm on their inner walls were cut and placed in 5 mL test tubes in different decontaminating solutions.

The test tubes were then left for 18-24 hours at 21 0 C. Each section was then washed with distilled water and slit longitudinally to expose the biofilm on their inner walls and observed with a binocular microscope or by scanning electromicroscopy.

Alternatively, the same procedure was followed on plastic plates coated with bacteria. The solutions that showed a significant eradication of the biofilm are listed in Table 1.

18 JUN '99 15:31 61 02 62853593 PAGE. 014 18/06 '99 FRI 15:30 FAX 61 02 62853593I.AURLA j1 I.P AUSTRALIA IM 015 9 TAB3LE 1 Substance* Biofilm Remarks*** presence* Control

H

2 0 2 PAA SDS EDTA

MA+

LA CPC

GLU+

Solutiona 0 Solution without PAA 0 PPT Tween 20Tm Betadine

H

2 02 PAA

H

2 0 2 SDS

H

2 02 EDTA H1202 MA

H

2 0 2 +LA H1202 CPC

H

2 0 2 PAA LA

H

2 0 2 PAA SDS

H

2 0 2 +MA +LA 1 2 0 2 +MA +LA +SDS D H1202 SDS EDTA 0

H

2 0 2 +PAA +MA SDS EDTA SDS +EDTA +MA 0 PPT SDS +EDTA +CPC 0 PPT SDS EDTA PAA MA +LA MA +LA+ SDS 0 MA +LA +EDTA PPT MA +LA +SDS +EDTA 0 PPT 18 JUN '99 15:31 61 02 62853593 PAGE.015 18 JUN '99 15:31 61 02 62853593 PAGE. 015 18/06 '99 FRI 15:30 FAX 61 02 62853593 I.P AUSTRALIA M016 MA Mandelic acid, LA Lactic acid, GLU Glutaraldehyde, Peracetic acid PAA, Solution containing all elements listed supra, Control Tube without treatment, SDS Sodium dodecyl sulfate, CPC Cetylpyridinium chloride.

Solutions were tested directly on contaminated tubes. Results are expressed on a scale representing presence of a biofilm; 0= no biofilm, intact biofilm.

The solution precipitates.

a The solution contains the seven ingredients defined as one of the most advantageous mixtures. It may also contain five of the seven ingredients e.g. from which CPC and PAA are absent and SDS concentration is reduced from 2% to 1%.

A field test was conducted over a period of two weeks to four months to determine the cleaning and disinfecting efficacy of the compositions of the present invention. The composition was fed to the network of small diameter fresh water lines of a dentist's installation.

For comparative purposes, at the end of each work day, all the small diameter water pipes of the dentist's installation were filled with the diverse detergent-disinfectant combinations of the present invention, left overnight and the next morning thoroughly rinsed with water.

For each test, during the same work day, three water samples were drawn from various dental instruments, namely, an air/water gun, a high speed water turbine, and an ultrasonic tartar remover.

These samples were placed under favorable conditions for microorganism growth. After five to seven days, the microorganism colonies were counted. The results were surprisingly encouraging; after numerous tests on 18 JUN '99 15:32 61 02 62853593 PAGE. 016 18 JUN '99 15:32 61 02 62853593 PAGE. 016 18/06 '99 FRI 15:30 FAX 61 02 62853593 I.P AUSTRALIA M017 11 the various instruments, an almost complete abolition of the microbian counts was obtained for the effective combinations of Table 1, e.g. where the presence of biofilm is registered 0.

The following antiseptics commercially available have been experimented and none of them have shown any efficient decontaminating activity against a biofilm: BIOVAC" Chlorohexidine, 3.20% EDTA, proteolytic enzymes, a dispersing agent).

EFFERDENT"m (Potassium monopersulfate, Sodium borate, Sodium lauryl persulfate, Sodium bicarbonate, Magnesium stearate, Simethicone).

POLYDENT (Potassium monopersulfate, Tetrasodium pyrophosphate, Sodium bicarbonate, Sodium borate).

STERISOL' (Chlorohexidine, Glycerol, 38-F, Alcohol).

THERASOL

M (C-31G, NaF, Glycerine, Alcohol).

GLUTARALDEHYDE

ALCOHOL PATHEX" (Phenolic) SODIUM HYPOCHLORITE 2%.

Apparently, none of these preparations fulfill essential criteria for decontaminating surfaces coated with a biofilm, e.g. a detergent component, a denaturing and matrix-disintegrating component and a bactericide.

Although the present invention has been described hereinabove by way of preferred embodiments thereof, these embodiments can be modified at will, within the scope of the appended claims, without departing from the spirit and nature of the subject invention.

18 JUN '99 15:32 61 02 62853593 PAGE- 017 18 JUN '99 15:32 61 02 62853593 PAGE. 017

Claims (2)

1. An aqueous cleaning and disinfecting composition for use in decontaminating surfaces being susceptible to contamination by microorganisms and being susceptible to the formation of a biofilm thereon, said composition comprising 1% (w/v) ethylenediamine tetraacetic acid, 5% hydrogen peroxide, and 1 to 2% sodium dodecyl sulfate (SDS).

2. The composition of claim 1 in which the balance to 100% is water. DATED this 28th day of April 1999 UNIVERSITE DE MONTREAL By their Patent Attorneys CULLEN CO. 18 JUN '99 15:32 61 02 62853593 PAGE.018