Comparative in vitro activity of quinupristin/dalfopristin and seven other antimicrobials against methicillin-susceptible and methicillin-resistant nosocomial Staphylococcus aureus bloodstream isolates.

Staphylococcus aureus strains resistant to a variety of antimicrobial agents are often found in the hospital environment and are responsible for many life-threatening infections. The activity of quinupristin/dalfopristin against 84 Staphylococcus aureus bloodstream isolates (both methicillin resistant and methicillin sensitive) was compared to the activity of vancomycin, teicoplanin, erythromycin, oxacillin, clindamycin, gentamicin, rifampicin. The Minimum Inhibitory Concentrations of these agents was evaluated with the Epsilometer Test. Quinupristin/dalfopristin inhibited all methicillin-sensitive strains at 1mg/L, and 75% of methicillin-resistant strains at 1.5mg/L. According to these results, quinupristin-dalfopristin shows promising in-vitro activity and may be a welcome alternative treatment for methicillin-resistant staphylococcal infections, resulting in reduced use of glycopeptides.