Oxazolidinone susceptibility patterns for 2005: International Report from the Zyvox® Annual Appraisal of Potency and Spectrum Study

The international (non-USA) ZAAPS Program has accumulated 4 years of linezolid resistance surveillance results tracking infections caused by organisms with evolving resistance profiles. The major organism groups monitored were: Staphylococcus aureus and coagulase-negative staphylococci (including methicillin [oxacillin]-resistant strains), enterococci (including vancomycin-resistant [VRE] strains), Streptococcus pneumoniae (including multidrug-resistant [MDR] strains), viridans group streptococci and β-haemolytic streptococci (4209 isolates overall). No linezolid-resistant strains were detected from the 16 monitored nations participating in 2005, consistent with previously reported 2002-2004 results. Linezolid remains highly active against Gram-positive strains including MRSA (MIC90, 2 mg/L). With MDR in Gram-positive organisms increasing in prevalence, continued surveillance of linezolid appears to be prudent practice as linezolid becomes more widely prescribed for these difficult-to-treat infections.