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

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 MIC90 range, 1 to 4 microg/ml) or vancomycin susceptibility for enterococci (MIC90 range, 1 to 4 microg/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.