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. 1991 Oct;35(10):1997–2002. doi: 10.1128/aac.35.10.1997

Chlorhexidine resistance in methicillin-resistant Staphylococcus aureus or just an elevated MIC? An in vitro and in vivo assessment.

B D Cookson 1, M C Bolton 1, J H Platt 1
PMCID: PMC245314  PMID: 1759820

Abstract

Chlorhexidine (Hibiscrub; ICI) is generally accepted to be effective as an antiseptic hand wash for methicillin-susceptible Staphylococcus aureus (MSSA), but there is dispute whether the chlorhexidine MIC for methicillin-resistant S. aureus (MRSA) strains is higher than that for MSSA strains and, indeed, whether it is relevant. In addition, the link between resistance to chlorhexidine, gentamicin, and "nucleic acid-binding" compounds (NAB; which code, in particular, for propamidine isethionate and ethidium bromide) requires clarification. We performed chlorhexidine MIC and rate of kill tests on a number of MSSA and MRSA isolates. Two gentamicin-resistant MRSA isolates without NAB plasmids were more susceptible (0.25 and 0.5 microgram/ml) than four of eight MSSA that we tested (range, 0.25 to 2 microgram/ml). Chlorhexidine MICs were higher (4 to 8 micrograms/ml) for seven distinct MRSA isolates with plasmids conveying resistance to gentamicin and NAB (GNAB). Curing of the GNAB plasmid from MRSA strains resulted in a fall in the MIC (1 to 3.3 micrograms/ml), but no consistent fall in killing by chlorhexidine was observed. No effect on the chlorhexidine MIC or killing was observed when we cured strains of methicillin resistance. GNAB plasmid transfer resulted in a rise in the chlorhexidine MIC for the strains but not consistent fall in killing by chlorhexidine. Ethical approval was granted for 10 volunteers to each have a methicillin-susceptible, GNAB-resistant, derived transcipient and its GNAB-susceptible isogenic parent applied to separate sites in an in vivo skin test; no significant difference was seen in survival rates after the application of chlorhexidine. These results suggest that chlorhexidine appears to be as effective as a hand-washing agent for MRSA isolates with or with out NAB plasmids as it is for MSSA isolates.

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1997

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Al-Masaudi S. B., Day M. J., Russell A. D. Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants. J Appl Bacteriol. 1988 Oct;65(4):329–337. doi: 10.1111/j.1365-2672.1988.tb01899.x. [DOI] [PubMed] [Google Scholar]
  2. Ayliffe G. A., Babb J. R., Davies J. G., Newsom S. W., Rowland C., Platt J. H., Mason B. Hygienic hand disinfection tests in three laboratories. J Hosp Infect. 1990 Aug;16(2):141–149. doi: 10.1016/0195-6701(90)90058-v. [DOI] [PubMed] [Google Scholar]
  3. Brumfitt W., Dixson S., Hamilton-Miller J. M. Resistance to antiseptics in methicillin and gentamicin resistant Staphylococcus aureus. Lancet. 1985 Jun 22;1(8443):1442–1443. doi: 10.1016/s0140-6736(85)91863-x. [DOI] [PubMed] [Google Scholar]
  4. Coleman D. C., Pomeroy H., Estridge J. K., Keane C. T., Cafferkey M. T., Hone R., Foster T. J. Susceptibility to antimicrobial agents and analysis of plasmids in gentamicin- and methicillin-resistant Staphylococcus aureus from Dublin hospitals. J Med Microbiol. 1985 Oct;20(2):157–167. doi: 10.1099/00222615-20-2-157. [DOI] [PubMed] [Google Scholar]
  5. Cookson B. D., Phillips I. Epidemic methicillin-resistant Staphylococcus aureus. J Antimicrob Chemother. 1988 Apr;21 (Suppl 100):57–65. doi: 10.1093/jac/21.suppl_c.57. [DOI] [PubMed] [Google Scholar]
  6. Cookson B., Talsania H., Naidoo J., Phillips I. Strategies for typing and properties of epidemic methicillin-resistant Staphylococcus aureus. Eur J Clin Microbiol. 1986 Dec;5(6):702–709. doi: 10.1007/BF02013309. [DOI] [PubMed] [Google Scholar]
  7. Emslie K. R., Townsend D. E., Grubb W. B. A resistance determinant to nucleic acid-binding compounds in methicillin-resistant Staphylococcus aureus. J Med Microbiol. 1985 Oct;20(2):139–145. doi: 10.1099/00222615-20-2-139. [DOI] [PubMed] [Google Scholar]
  8. Guidelines for the control of epidemic methicillin-resistant Staphylococcus aureus. Report of a combined working party of the Hospital Infection Society and British Society for Antimicrobial Chemotherapy. J Hosp Infect. 1986 Mar;7(2):193–201. [PubMed] [Google Scholar]
  9. Lacey R. W., Stokes A. Studies on recently isolated cultures of methicillin-resistant Staphylococcus aureus. J Gen Microbiol. 1979 Oct;114(2):329–339. doi: 10.1099/00221287-114-2-329. [DOI] [PubMed] [Google Scholar]
  10. Mycock G. Methicillin/antiseptic-resistant Staphylococcus aureus. Lancet. 1985 Oct 26;2(8461):949–950. doi: 10.1016/s0140-6736(85)90881-5. [DOI] [PubMed] [Google Scholar]
  11. Platt J. H., Bucknall R. A. MIC tests are not suitable for assessing antiseptic handwashes. J Hosp Infect. 1988 May;11(4):396–397. doi: 10.1016/0195-6701(88)90095-3. [DOI] [PubMed] [Google Scholar]
  12. STORY P. Testing of skin disinfectants. Br Med J. 1952 Nov 22;2(4794):1128–1130. doi: 10.1136/bmj.2.4794.1128. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. SWANSTROM M., ADAMS M. H. Agar layer method for production of high titer phage stocks. Proc Soc Exp Biol Med. 1951 Nov;78(2):372–375. doi: 10.3181/00379727-78-19076. [DOI] [PubMed] [Google Scholar]
  14. Sheikh W. Development and validation of a neutralizer system for in vitro evaluation of some antiseptics. Antimicrob Agents Chemother. 1981 Mar;19(3):429–434. doi: 10.1128/aac.19.3.429. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Tennent J. M., Lyon B. R., Midgley M., Jones I. G., Purewal A. S., Skurray R. A. Physical and biochemical characterization of the qacA gene encoding antiseptic and disinfectant resistance in Staphylococcus aureus. J Gen Microbiol. 1989 Jan;135(1):1–10. doi: 10.1099/00221287-135-1-1. [DOI] [PubMed] [Google Scholar]
  16. Townsend D. E., Ashdown N., Bolton S., Bradley J., Duckworth G., Moorhouse E. C., Grubb W. B. The international spread of methicillin-resistant Staphylococcus aureus. J Hosp Infect. 1987 Jan;9(1):60–71. doi: 10.1016/0195-6701(87)90097-1. [DOI] [PubMed] [Google Scholar]
  17. Yamamoto T., Tamura Y., Yokota T. Antiseptic and antibiotic resistance plasmid in Staphylococcus aureus that possesses ability to confer chlorhexidine and acrinol resistance. Antimicrob Agents Chemother. 1988 Jun;32(6):932–935. doi: 10.1128/aac.32.6.932. [DOI] [PMC free article] [PubMed] [Google Scholar]

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