Activity of daptomycin against susceptible and multidrug-resistant Gram-positive pathogens collected in the SECURE study (Europe) during 2000-2001

Abstract

Antibiotic resistance was prevalent in Gram-positive pathogens collected from 40 sites in 15 European countries during 2000-2001. Among Staphylococcus aureus, 27.3% of all isolates submitted were resistant to oxacillin and ranged from 0% of isolates from the Netherlands to 36.9% of isolates from Portugal. The overall prevalence of vancomycin-resistant Enterococcus faecium was 25.1%, with Italy submitting the largest percentage of resistant isolates (60.6%). For Streptococcus pneumoniae, 9.4% of all isolates collected were resistant to penicillin with variation by country from 0% in the Netherlands to 20.7% in Portugal. Multidrug resistance (MDR), defined as concurrent resistance to three or more antimicrobials of different chemical classes, was observed in 24.6% of S. aureus, 19.6% of E. faecium and 3.6% of S. pneumoniae. The directed spectrum agents daptomycin, linezolid and quinupristin-dalfopristin were active in vitro against all isolates regardless of their resistance to other agents. Daptomycin and quinupristin-dalfopristin (MIC(90)s 0.5 mg/L) were equally active against oxacillin-resistant S. aureus compared with linezolid (MIC(90) 2 mg/L). The activities of daptomycin, quinupristin-dalfopristin and linezolid were not affected by resistance to vancomycin in E. faecium (MIC(90)s of 4, 2 and 2 mg/L, respectively). Daptomycin was more active against penicillin-resistant S. pneumoniae (MIC(90) 0.25 mg/L) than was quinupristin-dalfopristin (MIC(90) 0.5 mg/L) or linezolid (MIC(90) 2 mg/L). Daptomycin was highly active against clinically important Gram-positive pathogens, including those that were multiply resistant to currently available agents. The results of this study provide a benchmark of the activity of daptomycin against contemporary European isolates and will serve as a baseline to monitor future changes in the susceptibility of these organisms to daptomycin.