Antimicrobial resistance of Staphylococcus aureus isolated from skin infections and its implications in various clinical conditions in Korea

Background: Periodic investigations into patterns of antimicrobial resistance can help to optimize the efficacy of treatment and limit the development of resistance. Objectives: The aim of this study was to update information on patterns of antimicrobial resistance in Staphylococcus aureus isolated from skin infections in South Korea. Methods: We retrospectively analyzed clinical information and in vitro antimicrobial resistance data for 965 clinical S. aureus isolates obtained from skin infections during 2010-2013 in a university hospital in South Korea. Results: The rate of resistance to oxacillin (methicillin-resistant S. aureus [MRSA]) was 47.4%. Similar rates of resistance to erythromycin (45.6%), fusidic acid (44.0%), and clindamycin (42.3%) were noted. The rate of resistance to mupirocin was 8.4%. Overall, 4.9% of isolates were resistant to both fusidic acid and mupirocin. None of the isolates showed resistance to habekacin, synercid, teicoplanin, or vancomycin. Generally, antimicrobial resistance rates did not increase from 2010 to 2013 except with reference to a few agents such as mupirocin and rifampin. Isolates from surgical patients, inpatients, non-dermatology outpatients, and adult patients showed relatively high rates of resistance to multiple antimicrobials. Resistance to mupirocin was not only lower than that to fusidic acid but was consistent across clinical contexts. Conclusions: The prevalence of MRSA in skin infections in South Korea did not increase during 2010-2013. Isolates from dermatology outpatients showed relatively lower rates of resistance to multiple antimicrobials than isolates from non-dermatology outpatients. Among topical antimicrobials, resistance to mupirocin was relatively low regardless of clinical condition.