In vitro activities of daptomycin, vancomycin, linezolid, and quinupristin-dalfopristin against staphylococci and enterococci, including vancomycin-intermediate and -resistant strains

The in vitro activity of daptomycin was compared with those of vancomycin, linezolid, and quinupristin-dalfopristin against a variety (n = 203) of gra m-positive bacteria, including methicillin resistant Staphylococcus aureus and S. epidermidis (MRSA and MRSE, respectively), vancomycin resistant ente rococci (VRE), and vancomycin-intermediate S. aureus (VISA). Overall, dapto mycin was more active against all organisms tested, except Enterococcus fae cium and VISA, against which its activity was similar to that of quinuprist in-dalfopristin. In time-kill studies with MRSA, MRSE, VRE, and VISA, dapto mycin demonstrated greater bactericidal activity than all other drugs teste d, killing greater than or equal to 3 log CFU/ml by 8 h. Daptomycin may be a potential alternative drug therapy for multidrug-resistant gram-positive organisms and warrants further investigation.