In vitro activity of dalbavancin and telavancin against staphylococci and streptococci isolated from patients in Canadian hospitals: results of the CANWARD 2007–2009 study

Two novel lipoglycopeptides, dalbavancin and telavancin, and relevant comparative agents were tested for in vitro activity against clinical isolates of staphylococci and streptococci collected in the cross-Canada surveillance study, CANWARD, in 2007–2009. The rank order of potency (based on MIC90 [μg/mL], i.e., the concentration of antimicrobial agent required to inhibit the growth of 90% of isolates tested) of glycopeptides against both Staphylococcus aureus and Staphylococcus epidermidis was dalbavancin (0.06 μg/mL) >telavancin (0.5 μg/mL) > vancomycin (1–2 μg/mL); concurrent susceptibility or resistance to oxacillin in staphylococci did not affect potency of glycopeptides. Dalbavancin and telavancin also demonstrated potent activity against Streptococcus pneumoniae, including penicillin-resistant isolates (MIC90, ≤0.03 μg/mL; ≤0.06 μg/mL), and Streptococcus pyogenes (≤0.03 μg/mL; 0.06 μg/mL). Based on their robust in vitro activities, dalbavancin and telavancin have the potential to treat Gram-positive infections caused by methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae.