Daptomycin in vitro susceptibility in European Gram-positive clinical isolates

The objective of this study was to determine the activity of daptomycin, a novel lipopeptide, against European Gram-positive isolates (n = 1539). The MIC(90)-values of daptomycin against Staphylococcus aureus isolates was 0.25 mg/L, against Enterococcus faecalis 4 mg/L, against Enterococcus faecium 8 mg/L, 0.25 mg/L against Staphylococcus epidermidis, and 0.25mg/L against Streptococcus pneumoniae. Daptomycin was equally potent against antibiotic-susceptible and resistant strains within a particular species. Based on a breakpoint of 1 mg/L for S. aureus and group A streptococci, all isolates tested were susceptible to daptomycin. Based on a breakpoint of 4 mg/L for vancomcyin-susceptible E. faecalis 99.7% of these isolates were susceptible to daptomycin.