Telavancin:: in vitro activity against staphylococci in a biofilm model

Objectives: To assess the in vitro activity of the novel lipoglycopeptide telavancin against staphylococcal biofilms using an in vitro pharmacokinetic model. Methods: Using the Sorbarod model, biofilms were established. The strains tested included methicillin-susceptible and -resistant strains of Staphylococcus aureus and coagulase-negative staphylococci, as well as glycopeptide-intermediate S. aureus (GISA). The biofilms were exposed to exponentially decreasing concentrations of telavancin and four comparator antibiotics, vancomycin, teicoplanin, linezolid and moxifloxacin and the bactericidal activity of the antibiotics was assessed. The concentrations of the antibiotics used in these experiments corresponded to peak serum levels achievable in humans and the rates at which drug concentrations were decreased corresponded to their elimination half-lives. Results: All of the drugs tested produced a reduction in the number of bacteria eluted from the biofilms. Telavancin was more effective than the commercially available glycopeptides, vancomycin and teicoplanin, and of the three, was the most active agent against both the non-GISA and GISA strains. Of all the antibiotics tested, moxifloxacin produced the greatest reduction in biofilm cells, but only against the non-GISA strains. Conclusions: Telavancin exhibited substantial antimicrobial activity against staphylococcal biofilms, including GISA strains. This study supports the case for the evaluation of telavancin in the treatment of staphylococcal biofilm-associated infections.