Update of the in vitro activity of daptomycin tested against 6710 Gram-positive cocci isolated in North America (2006).

Gram-positive bacterial strains (6710) consecutively collected during 2006 in hospitals located in the United States and Canada were tested by reference broth microdilution methods against daptomycin and comparison agents. Only 1 Staphylococcus aureus strain (0.01%) had nonsusceptible daptomycin MIC value as specified by published break points. S. aureus daptomycin MIC distributions from 2006 as compared with those of previous years did not show "MIC creep". Resistance to other compounds, such as vancomycin, oxacillin, and penicillin, did not adversely influence daptomycin activity. Daptomycin remains highly active against clinical Gram-positive isolates collected in North America.