Telavancin activity in vitro tested against a worldwide collection of Gram-positive clinical isolates (2014)

Abstract

Objectives: Telavancin activity was measured against Gram-positive pathogens collected worldwide during 2014 using the revised broth microdilution testing method. The results were compared with previous reports.

Methods: A total of 10552 isolates from 86 sites located in 32 countries were included as part of the Telavancin International Surveillance Program for the Americas, Europe and Asia-Pacific.

Results: Telavancin had MIC₅₀ and MIC₉₀ values of 0.03μg/mL and 0.06μg/mL, respectively, against Staphylococcus aureus, regardless of methicillin susceptibility, and inhibited all S. aureus isolates at the CLSI breakpoint (≤0.12μg/mL). Telavancin was eight-fold more active than daptomycin (MIC_50/90, 0.25/0.5μg/mL) and 16-32-fold more active than vancomycin (MIC_50/90, 1/1μg/mL) and linezolid (MIC_50/90, 1/1μg/mL) against methicillin-resistant S. aureus (MRSA). Telavancin was also active against coagulase-negative staphylococci isolates (MIC_50/90, 0.06/0.06μg/mL). Vancomycin-susceptible Enterococcus faecalis isolates (n=718) were all inhibited by telavancin (MIC_50/90, 0.12/0.12μg/mL) at ≤0.25μg/mL (CLSI breakpoint), except for a single isolate (MIC, 0.5μg/mL). All Enterococcus faecium and E. faecalis isolates with telavancin MICs of ≥0.5μg/mL and ≥1μg/mL, respectively, had a VanA phenotype. Based on the MIC₉₀ values, telavancin was at least eight-fold more potent than comparators against vancomycin-susceptible enterococci. With the exception of Streptococcus agalactiae (MIC₅₀, 0.03μg/mL), all tested species of streptococci exhibited telavancin MIC₅₀ values of ≤0.015μg/mL.

Conclusions: These in vitro results from 2014 highlight the potent in vitro activity of telavancin and demonstrate that its activity was virtually unchanged compared with the corresponding 2013 telavancin surveillance results.

Keywords: Broth microdilution; Lipoglycopeptide; Surveillance; Susceptibility.