Impact of the suspending medium on susceptibility of meticillin-resistant Staphylococcus aureus to hydrogen peroxide vapour decontamination.

Several factors influence the in vitro susceptibility of microbes to disinfectants. We evaluated the impact of various suspending media on the susceptibility of meticillin-resistant Staphylococcus aureus (MRSA) to hydrogen peroxide vapour (HPV) decontamination. From a >6 log(10) inoculum, relative susceptibility was 10% bovine serum albumin (BSA) < TSB < 3% BSA < saline < 0.3% BSA = water. MRSA was not recovered after >60 min exposure to HPV for all suspensions. These findings indicate that the suspending medium has an effect on the in vitro susceptibility of MRSA to HPV, which may have implications in the case of suboptimal cleaning.