An in vitro study to determine the minimal bactericidal concentration of sodium hypochlorite (bleach) required to inhibit meticillin-resistant Staphylococcus pseudintermedius strains isolated from canine skin.

Abstract

BACKGROUND: Meticillin-resistant Staphylococcus pseudintermedius (MRSP) is becoming a more common pathogen in animals treated in veterinary hospitals, raising concerns for transmission and possible contamination of the hospital itself. The identification of effective agents for the decontamination of veterinary patients and hospitals is crucial. Sodium hypochlorite (6.15%) or 'bleach' is an inexpensive and frequently used decontamination agent in human and veterinary hospitals and an adjunctive treatment for human patients. There are no published data on the minimal bactericidal concentration (MBC) of sodium hypochlorite (6.15%) for MRSP. HYPOTHESIS/OBJECTIVES: The objective of this study was to determine the MBC of sodium hypochlorite (6.15%) against MRSP strains isolated from canine skin. METHODS: In this in vitro study, 12 canine skin isolates were obtained from the Antech Diagnostics microbiology department. Twofold serial dilutions of sodium hypochlorite (6.15%) were allowed to react with each of the MRSP strains for 15 min, followed by overnight incubation on agar plates. Colonies on each plate were counted. This process was repeated in triplicate. RESULTS: The overall MBC for the canine skin-isolated MRSP strains was 1:32, but most strains had an MBC between 1:64 and 1:128 dilution. CONCLUSIONS AND CLINICAL IMPORTANCE: This study shows that sodium hypochlorite (6.15%) is an effective agent for decontamination at easily achievable concentrations.