High Prevalence of Mupirocin Resistance in Staphylococcus aureus Isolates from a Pediatric Population

Abstract

ABSTRACTTopical mupirocin is used widely to treat skin and soft tissue infections and to eradicate nasal carriage of methicillin-resistantStaphylococcus aureus(MRSA). Few studies to date have characterized the rates ofS. aureusmupirocin resistance in pediatric populations. We retrospectively studied 358 uniqueS. aureusisolates obtained from 249 children seen in a predominantly outpatient setting by the Division of Pediatric Dermatology at a major academic center in New York City between 1 May 2012 and 17 September 2013. Mupirocin resistance rates and the associated risk factors were determined using a logistic regression analysis. In our patient population, 19.3% of patients had mupirocin-resistantS. aureusisolates at the time of their first culture, and 22.1% of patients withS. aureusinfection had a mupirocin-resistant isolate at some time during the study period. Overall, 31.3% of allS. aureusisolates collected during the study period were resistant to mupirocin. Prior mupirocin use was strongly correlated (odds ratio [OR] = 26.5;P= <0.001) with mupirocin resistance. Additional risk factors for mupirocin resistance included methicillin resistance, atopic dermatitis (AD), epidermolysis bullosa (EB), immunosuppression, and residence in northern Manhattan and the Bronx. Resistance to mupirocin is widespread in children with dermatologic complaints in the New York City area, and given the strong association with mupirocin exposure, it is likely that mupirocin use contributes to the increased resistance. Routine mupirocin testing may be important for MRSA decolonization strategies or the treatment of minor skin infections in children.