Frequent Use of Chlorhexidine-Based Body Wash Associated with a Reduction in Methicillin-Resistant Staphylococcus aureus Nasal Colonization among Military Trainees

In a field-based trial among military trainees, personal hygiene measures, including chlorhexidine (CHG) body wash, did not prevent overall and methicillin-resistantStaphylococcus aureus (MRSA) skin and soft-tissue infections (SSTI). We conducted a secondary analysis of anterior nares cultures obtained during the trial to evaluate the impact of hygiene measures onStaphylococcus aureus colonization. A cluster-randomized trial for SSTI prevention was conducted among U.S. Army infantry trainees from May 2010 to January 2012. There were three study groups with incrementally increasing education- and hygiene-based components: standard (S), enhanced standard (ES), and CHG. Anterior nares cultures were obtained from participants to determine the prevalence ofS. aureus colonization. A total of 1,706 participants (469 S, 597 ES, and 640 CHG) without SSTI were included in the colonization analysis. Of those randomized to the CHG group, 360 (56.3%) reported frequent use of body wash. Frequent use of body wash had no effect on overallS. aureus colonization (53.3% versus 56.8% among infrequent/nonusers;P = 0.25). MRSA colonization prevalence was marginally lower among frequent users (2.5% versus 4.7%;P = 0.07). In multivariable analysis, the odds of MRSA colonization were lower among frequent users (odds ratio [OR], 0.36; 95% confidence interval [CI], 0.16 to 0.77). This CHG-associated reduction was not observed when comparing colonization with USA300 to that with non-USA300 types (OR, 0.59; 95% CI, 0.06 to 5.76). Frequent use of CHG body wash was associated with a reduction in MRSA nasal colonization among high-risk military trainees. Topical chlorhexidine may contribute to MRSA SSTI prevention by reducing colonization. However, further studies evaluating the pathogenesis of SSTI are needed. (This study has been registered at ClinicalTrials.gov under registration no. NCT01105767).