In vitro activity of linezolid, quinupristin-dalfopristin, vancomycin, teicoplanin, moxifloxacin and mupirocin against methicillin-resistant Staphylococcus aureus: comparative evaluation by the E test and a broth microdilution method.

The E test and broth microdilution showed comparable accuracy for the susceptibility testing of methicillin-resistant S. aureus (MRSA). All of the 109 primary clinical MRSA isolates were fully susceptible to the glycopeptides vancomycin and teicoplanin, the oxazolidinone linezolid, and the streptogramin quinupristin-dalfopristin. Nine out of the 109 MRSA isolates (8.3 percent) demonstrated resistance to moxifloxacin and 5 out of the 109 strains (4.6 percent) were resistant to the topical agent mupirocin. Linezolid and quinupristin-dalfopristin may prove useful alternatives for the treatment of patients with MRSA infections. MRSA isolates should be screened for in vitro susceptibility against mupirocin prior to the topical application.