[Methicillin resistant Staphylococcus aureus and glycopeptides (vancomycin, teicoplanin): in vitro selection of...

By repeated and successive treatments of five strains of methicillin-resistant Staphylococcus aureus with sub-inhibitory concentrations of vancomycin and of teicoplanin, the authors have confirmed that selection of resistant strains could be obtained more easily with teicoplanin than with vancomycin. Moreover, we have shown that treatments with subinhibitory concentrations of teicoplanin could also influence the activity of vancomycin, although the strains have never been in contact with the latter antibiotic. This could account, at least in part, for the downhill evolution of the activity of glycopeptides against staphylococci, observed this last years. Indeed, the efficacy of these antibiotics upon which treatment of severe infections due to multiresistant staphylococci relies, is lowering. Considering the challenge, this risk is worth being not only evaluated by a reinforced epidemiologic surveillance, but also limited by more severe criteria for the prescription and the follow-up of treatments with glycopeptides.