Incision and drainage is the primary therapy for uncomplicated MRSA skin infections. Available evidence suggests that most uncomplicated MRSA skin infections respond well to drainage alone (17). It has not been established through controlled studies whether certain patients benefit from ancillary antimicrobial therapy (18); however, experts have recommended that clinicians consider administering antimicrobial therapy in addition to drainage on the basis of such factors as patient age, immunosuppression, severity of local symptoms, and presence of fever (19). Several oral treatment options are available for patients in whom the clinician feels that antibiotics are required, even if the infecting isolate is pUSA03-positive. For example, isolates with tetracycline resistance (typically conferred by the tetK gene, located on a separate plasmid), generally retain in vitro susceptibility to minocycline and doxycycline (8). Resistance to trimethoprim–sulfamethoxazole is rare in MRSA USA300. Despite these available treatment options, we should be alert for isolates that are resistant to antimicrobials, because genetic elements encoding resistance to antimicrobial agents, such as trimethoprim, aminoglycosides, and vancomycin, are easily integrated into the pUSA03 genome (7). For this reason, we should monitor antimicrobial susceptibilities in S. aureus isolates in populations where pUSA03-positive strains are prevalent, even after empirical therapy has been modified to provide MRSA coverage.