Clinical features and antimicrobial treatment of skin infections caused by Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus

Skin infections caused by Panton-Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA), especially the USA300 clone, have been increasing in Japan. To prevent an epidemic of PVL-positive MRSA, rapid diagnosis and effective antimicrobial therapy are essential. However, the clinical features of, and antimicrobial efficacy against, these skin infections are not well understood in Japan. Here, we report 10 cases of skin infections caused by PVL-positive MRSA that presented over a two-year period in our clinic. Genetic analyses revealed that 90% of the PVL-positive MRSA strains were identified as USA300 and its related clones. Notably, 70% of the patients had atopic dermatitis (AD) as an underlying disease. Average durations of antimicrobial therapy for AD patients (10.6 weeks) were 2.9-fold longer than those for non-AD patients (3.7 weeks). However, all cases were improved by a long-term course of fosfomycin, minocycline, doxycycline, and/or rifampicin. Our data suggest that AD may be an important risk factor for intractable skin infections caused by PVL-positive MRSA.