LIMITED EFFECTIVENESS OF CHLORHEXIDINE BASED HAND DISINFECTANTS AGAINST METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS (MRSA)

Hand disinfectants containing chlorhexidine are thought to be less bac tericidal against methicillin-resistant Staphylococcus aureus (MRSA) t han methicillin-susceptible Staphylococcus aureus (MSSA). We report an in vitro comparison between three distinct MRSA strains and three MSS A strains. The bactericidal efficacy of chlorhexidine digluconate, 'Hi biscrub' and 'Hibisol' against Staphylococcus aureus was determined in a quantitative suspension test. Logarithmic reduction factors (RF) we re calculated for each of six parallel experiments. Chlorhexidine digl uconate and 'Hibisol' showed RF>5 at most concentrations and reaction times but 'Hibiscrub' did not. MRSA was found to be significantly less susceptible than MSSA, to chlorhexidine digluconate, 'Hibiscrub' and 'Hibisol' (P<0.05; two-tailed t-test for independent samples). 'Hibiso l' was significantly more effective against MRSA than 'Hibiscrub' (P<0 .05). Hand disinfectants containing both alcohol and chlorhexidine (e. g., 'Hibisol') are more effective against MRSA than scrubs based only on chlorhexidine ('Hibiscrub') and should be used in clinical practice .