Comparative In Vitro Activities and Postantibiotic Effects of the Oxazolidinone Compounds Eperezolid (PNU-100592) and Linezolid (PNU-100766) versus Vancomycin against Staphylococcus aureus , Coagulase-Negative Staphylococci, Enterococcus faecalis , and Enterococcus faecium

Abstract

ABSTRACT The activities of the oxazolidinone antibacterial agents eperezolid (PNU-100592) and linezolid (PNU-100766) were compared with that of vancomycin against clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus ( n = 200), coagulase-negative staphylococci ( n = 100), and vancomycin-susceptible and -resistant Enterococcus faecalis and Enterococcus faecium ( n = 50). Eperezolid and linezolid demonstrated good in vitro inhibitory activity, regardless of methicillin susceptibility for staphylococci (MIC at which 90% of the isolates are inhibited [MIC 90 ] range, 1 to 4 μg/ml) or vancomycin susceptibility for enterococci (MIC 90 range, 1 to 4 μg/ml). In time-kill studies, eperezolid and linezolid were bacteriostatic in action. A postantibiotic effect of 0.8 ± 0.5 h was demonstrated for both eperezolid and linezolid against S. aureus , S. epidermidis , E. faecalis , and E. faecium.