Daptomycin activity tested against 164 457 bacterial isolates from hospitalised patients: Summary of 8 years of a Worldwide Surveillance Programme (2005–2012)

We report the results of 8 years (2005–2012) of the Daptomycin Surveillance Programme Worldwide. Consecutive non-duplicate bacterial isolates (prevalence design) were collected from patients with documented infections in 410 medical centres and were susceptibility tested by reference broth microdilution methods. A total of 164 457 Gram-positive isolates were evaluated, including 97 542 Staphylococcus aureus, 21 413 coagulase-negative staphylococci (CoNS), 29 619 enterococci and 15 883 β-haemolytic streptococci. The prevalence of daptomycin-non-susceptible isolates was extremely low for all species in all geographic regions. Overall, the highest occurrence of non-susceptible isolates was observed among CoNS (0.19%), followed by Enterococcus faecium (0.18%), S. aureus (0.05%), Enterococcus faecalis (0.02%) and β-haemolytic streptococci (0.00%). Moreover, no trend towards increased daptomycin resistance (non-susceptibility) was observed for any species in any geographic region during the study interval. Against S. aureus, the daptomycin MIC50/90 was 0.25/0.5 mg/L in all geographic regions (99.95% susceptible overall). Only 53 daptomycin-non-susceptible S. aureus isolates were observed and the vast majority (49; 92.5%) had a daptomycin MIC value only 1 log2 dilution above the published susceptible breakpoint. Daptomycin was also active against CoNS (MIC50/90, 0.25/0.5 mg/L; 99.81% susceptible), E. faecalis (MIC50/90, 1/2 mg/L; 99.98% susceptible), E. faecium (MIC50/90, 2/4 mg/L; 99.82% susceptible) including vancomycin-non-susceptible isolates (4521 isolates; MIC50/90, 2/2 mg/L; 99.76% susceptible), and β-haemolytic streptococci (MIC50/90, ≤0.06/0.25 mg/L; 100.0% susceptible). In conclusion, daptomycin has remained very active against indicated species worldwide, and no significant year-to-year or regional variation in daptomycin activity has been detected.