Telavancin activity against Gram-positive bacteria isolated from respiratory tract specimens of patients with nosocomial pneumonia

The antimicrobial activity of telavancin against 2279 clinical Gram-positive cocci obtained from patients with nosocomial pneumonia [NP; including those with ventilator-acquired pneumonia (VAP)] located in numerous medical centres worldwide was evaluated. A contemporary collection of 2279 non-duplicate consecutive Gram-positive clinical isolates were submitted from 87 hospitals located in North America (913 isolates), Latin America (222 isolates), Europe (690 isolates), and the Asia-Pacific region (454 isolates) as part of the international telavancin surveillance programme for 2007-08. Isolates were tested for susceptibility by the reference broth microdilution method (with 2%-5% lysed horse blood added for testing of streptococci). Interpretive criteria were those from CLSI (M100-S20, 2010) except for telavancin, for which the susceptible breakpoints approved by the US FDA were applied. Telavancin was highly active against Staphylococcus aureus (MIC90, 0.25 mg/L; 100% susceptible), coagulase-negative staphylococci (MIC90, 0.25 mg/L), Streptococcus pneumoniae (MIC90, 0.03 mg/L), viridans group streptococci (MIC90, 0.06 mg/L; 100% susceptible), beta-haemolytic streptococci (MIC90, 0.06 mg/L; 100% susceptible) and vancomycin-susceptible enterococci (MIC90, 0.5 mg/L; 100% susceptible). Telavancin inhibited all staphylococci at < 0.5 mg/L. Among enterococci non-susceptible to vancomycin (all Enterococcus faecium), telavancin was active against isolates exhibiting a VanB phenotype (MIC, 0.06-0.12 mg/L), but less potent against VanA strains (MIC, >= 2 mg/L). Telavancin demonstrated equal or greater potency than the comparators (vancomycin, teicoplanin, daptomycin, linezolid and quinupristin/dalfopristin) against Gram-positive pathogens implicated in NP. Telavancin showed elevated MIC values only against enterococcus isolates showing a VanA phenotype. The continued appearance of multidrug-resistant pathogens among Gram-positive isolates, mainly S. aureus, necessitates the introduction of new agents and longitudinal surveillance to monitor for the potential emergence of resistance.