Evaluation of chlorhexidine and povidone iodine activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis using a surface test.
Most published studies of the activity of biocides against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) have been based on suspension tests. This study was undertaken to provide information on the effect of chlorhexidine and povidone iodine on bacteria dried on to surfaces, a situation in which biocide activity is known to be reduced. The inactivation of MRSA (10 strains), methicillin-sensitive Staphylococcus aureus (MSSA, 10 strains), VRE (nine strains) and vancomycin-sensitive Enterococcus faecalis (VSE, 10 strains) by 0.5% aqueous chlorhexidine gluconate or 10% povidone iodine was evaluated by applying the European surface test method. Povidone iodine was equally active against resistant and sensitive strains of both species with microbicidal effects (ME), i.e. the log(10)concentration of micro-organisms compared with controls treated with distilled water, after 1.5 min of 3.14 and 3.49 for VRE and VSE respectively, and 3.47 and 3.78 for MRSA and MSSA. Chlorhexidine was equally active against VRE and VSE (ME 3.37 vs. 3. 56 after 7 min, respectively), but was significantly less active against MRSA as opposed to MSSA (ME 3.07 vs. 3.83 after 10 min, P= 0. 017).
Block
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C
Department of Clinical Microbiology and Infectious Diseases, Hadassah University Hospital, Jerusalem, Israel. block@hadassah.org.il
Robenshtok
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E
Simhon
A
A
Shapiro
M
M
D000891:Anti-Infective Agents, Local; D002710:Chlorhexidine; D003428:Cross Infection / Q000382:microbiology; D004202:Disinfectants; D004353:Drug Evaluation, Preclinical; D004352:Drug Resistance, Microbial; D013293:Enterococcus faecalis / Q000145:classification / Q000187:drug effects*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D017053:Infection Control; D007557:Israel; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011206:Povidone-Iodine; D012703:Serotyping; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects*; D013997:Time Factors; D020713:Vancomycin Resistance
D000891:Anti-Infective Agents, Local; D004202:Disinfectants; D011206:Povidone-Iodine; D002710:Chlorhexidine