Emerging multidrug resistance of methicillin-resistant Staphylococcus aureus in hand infections.

BACKGROUND Methicillin-resistant Staphylococcus aureus has been the most commonly identified pathogen in hand infections at urban centers, but the evolving antibiotic sensitivity profiles of methicillin-resistant Staphylococcus aureus are not known. The purposes of this study are to determine if multidrug resistance in methicillin-resistant Staphylococcus aureus is emerging and to provide current recommendations for empiric antibiotic selection for hand infections in endemic regions. METHODS An eight-year longitudinal, retrospective chart review was performed on all culture-positive hand infections encountered by an urban hospital from 2005 to 2012. The proportions of all major organisms were calculated for each year. Methicillin-resistant Staphylococcus aureus infections were additionally analyzed for antibiotic sensitivity. RESULTS A total of 683 culture-positive hand infections were identified. Overall, methicillin-resistant Staphylococcus aureus grew on culture in 49% of cases; the annual incidence peaked at 65% in 2007. Over the study period, methicillin-resistant Staphylococcus aureus was universally resistant to penicillin, oxacillin, and ampicillin. Clindamycin resistance significantly increased, approaching 20% by 2012 (p = 0.02). Levofloxacin resistance linearly increased from 12% to 50% (p < 0.01). Resistance to trimethoprim-sulfamethoxazole, tetracycline, gentamicin, and moxifloxacin was only sporadically observed. Resistance to vancomycin, daptomycin, linezolid, and rifampin was not observed. CONCLUSIONS Significant increases in resistance to clindamycin and levofloxacin were observed in recent years, and empiric therapy with these drugs may have limited efficacy, especially in urban centers. CLINICAL RELEVANCE Hand infections caused by methicillin-resistant Staphylococcus aureus may be developing increasing resistance to clindamycin and levofloxacin in recent years. This longitudinal study examines the effectiveness of a variety of antibiotics to methicillin-resistant Staphylococcus aureus.