Antimicrobial activity of dalbavancin tested against Gram-positive clinical isolates from Latin American medical centres

The activity of dalbavancin, a new semi-synthetic lipoglycopeptide antibiotic, was evaluated in comparison with other antibacterial agents against 1229 Gram-positive organisms collected from medical centres in Latin America. Dalbavancin was the most potent compound tested against isolates of Staphylococcus aureus (MIC50, 0.06 mg/L) and coagulase-negative staphylococci (MIC50, 0.03 mg/L), independently of methicillin susceptibility. Dalbavancin inhibited all Streptococcus pneumoniae isolates at less than or equal to 0.06 mg/L. Dalbavancin also demonstrated excellent activity against beta-haemolytic (MIC50, less than or equal to 0.008 mg/L) and viridans group (MIC50, 0.016 mg/L) streptococci. All vancomycin-susceptible Enterococcus spp. isolates were inhibited by dalbavancin at less than or equal to 0.25 mg/L, but some vancomycin-resistant Enterococcus spp. isolates were only inhibited by dalbavancin levels of greater than or equal to 8 mg/L. Dalbavancin exhibited excellent activity against isolates of Corynebacterium spp. and Listeria spp. Dalbavancin may provide an important therapeutic option for Gram-positive infections, excluding those caused by enterococci with VanA-type resistance.