In vitro activity of a novel oxazolidinone, AZD2563, against randomly selected and multiresistant Gram-positive cocci.

The in vitro activity of AZD2563, a novel oxazolidinone, was assessed against 595 Gram-positive cocci, comprising recent surveillance isolates and a collection of resistant (including multiresistant), epidemiologically diverse isolates. The MICs of AZD2563 for staphylococci, pneumococci and enterococci had narrow ranges, 0.25-2 mg/L, with modal MICs of 1 mg/L for staphylococci and pneumococci, and 1-2 mg/L for enterococci. AZD2563 was equally active against the surveillance isolates and those that had been selected for their multiresistance to other agents. The MICs of AZD2563 were either the same as those of linezolid or two-fold lower.