Prevalence of methicillin-resistant Staphylococcus aureus in a Canadian inner-city shelter.

BACKGROUND Methicillin-resistant Staphylococcus aureus (MRSA) colonization is increasingly of concern in community settings. However, despite a recent outbreak in Calgary, Alberta, data on the prevalence of MRSA in Canadian communities are lacking. Globally, few studies have been performed in high-risk groups such as inner-city populations. METHODS A cross-sectional study of the prevalence of MRSA among residents and staff at three Ottawa, Ontario, shelters was conducted. All participants completed a questionnaire, and provided nasal swabs as well as one of rectal, anal or groin swabs. RESULTS Among 84 participants, the prevalence of MRSA colonization was 2.4%. Among the resident subgroup, the prevalence was 4.5%, while no MRSA isolates were found among 40 staff participants. All isolates were USA100 (CMRSA-2) subtypes. CONCLUSIONS The prevalence of MRSA colonization among residents is higher than baseline population rates, but is consistent with other inner-city populations. Although community outbreaks of USA300 and USA400 strains are increasingly reported, movement of nosocomial strains (ie, USA100 [CMRSA-2]) into communities remains an important avenue in the spread of MRSA and underscores the importance of nosocomial MRSA control.