Update of the telavancin activity in vitro tested against a worldwide collection of Gram-positive clinical isolates (2013), when applying the revised susceptibility testing method

A revised broth microdilution susceptibility testing method for telavancin was approved by the Food and Drug Administration (FDA). Telavancin activity was assessed against Gram-positive pathogens collected worldwide (2013) using the revised method. A total of 12,346 isolates from 90 sites were included as part of the Telavancin International Surveillance Program for the Americas, Europe, and Asia-Pacific. Telavancin had MIC50 and MIC90 values of 0.03 and 0.06 μg/mL, respectively, against staphylococci, regardless of methicillin susceptibility, and inhibited all Staphylococcus aureus at ≤0.12 μg/mL (revised FDA breakpoint). Telavancin was 8-fold more active than daptomycin (MIC50/90, 0.25/0.5 μg/mL) and 16- to 32-fold more active than vancomycin (MIC50/90, 1/1 μg/mL) and linezolid (MIC50/90, 1/1 μg/mL) against methicillin-resistant S. aureus. All 692 vancomycin-susceptible Enterococcus faecalis were inhibited by telavancin (MIC50/90, 0.12/0.12 μg/mL) at ≤0.25 μg/mL (FDA breakpoint), except for 1 strain (MIC, 0.5 μg/mL). All Enterococcus faecium and E. faecalis with telavancin MIC values of ≥0.5 and ≥1 μg/mL, respectively, had a VanA phenotype. A comparison data analysis based on the MIC90 demonstrated that telavancin was at least 8-fold more potent than comparators against vancomycin-susceptible enterococci. Streptococci showed telavancin MIC50 values of ≤0.015 μg/mL, except for Streptococcus agalactiae (MIC50, 0.03 μg/mL). These in vitro results obtained by the recently approved susceptibility testing method establish a new benchmark of telavancin activity worldwide.