Chlorhexidine Does Not Select for Resistance in Staphylococcus aureus Isolates in a Community Setting

Abstract

Previously, a cluster-randomized, double-blind controlled trial was carried out to evaluate the effectiveness of 2% chlorhexidine gluconate (CHG) body cloths vs. control cloths (comfort bath (CB) non-medicated cleaning cloths) in reducing the incidence of skin and soft-tissue infection (SSTI) in a cohort of military recruits from the Marine Officer Candidate School, Quantico, Virginia, USA. This paper presents the substudy carried out to evaluate the incidence of CHG-resistant Staphylococcus aureus colonization among the recruits after repeated exposure. Among subjects assigned to the CHG group, those that were persistently colonized (i.e. had results positive for S. aureus in nares and/or axilla at baseline and at each biweekly visit) and reported using >=50% of cloths met criteria for evaluation and had each isolate assessed for CHG resistance. The same criteria were used for selection of subjects assigned to the CB group. A total of 160 S. aureus isolates from the CHG group (n=43) were tested for CHG resistance, including 25 isolates that were methicillin-resistant (MRSA). In the CHG group, a total of 6 isolates (3.8%) from 2 different subjects exhibited CHG resistance, all of which were MRSA. On the other hand, no CHG resistance was observed in 48 S. aureus isolates obtained from 20 subjects in the CB group. Overall, this study has identified few prevalent and no incident CHG-resistant S. aureus strains in a military recruit setting despite repeated exposure to CHG over time. These data support the safety of CHG use as part of a community-based decolonization and SSTI-prevention programme.