Assessment of telavancin minimal inhibitory concentrations by revised broth microdilution method in phase 3 complicated skin and skin-structure infection clinical trial isolates

- The rBMD method has improved the accuracy and reproducibility of telavancin MIC testing.
- The objective of this study was to analyze the S. aureus isolates recovered from complicated skin and skin-structure infections patients treated using the rBMD method and evaluate the impact of the revised MICs on the clinical cure and microbiological eradication rates.
- Telavancin MIC values obtained by the rBMD were up to 8-fold lower than the values obtained by the original BMD method and all isolates remained susceptible to telavancin at the 0.12 μg/mL breakpoint.
- The clinical cure and microbiological eradication rates were comparable for patients with S. aureus, methicillin-resistant S. aureus, and S. aureus isolates with elevated vancomycin MICs (≥1 μg/mL).
- With the revision of the BMD method, telavancin MICs more accurately represent telavancin's in vitro potency against S. aureus.

The broth microdilution (BMD) MIC testing method for telavancin was recently revised BMD (rBMD) to improve accuracy and reproducibility. Staphylococcus aureus isolates from telavancin phase 3 complicated skin and skin-structure infection (cSSSI) studies were tested using the rBMD method. Retesting of 1132 isolates produced MICs ranging from ≤0.015 to 0.12 μg/mL that were 8-fold lower than the original method. All isolates tested remained susceptible to telavancin at the revised susceptibility breakpoint of 0.12 μg/mL. The clinical cure and microbiological eradication rates were 90% (368/409) and 89% (366/409) for telavancin-treated patients, and were similar for patients with methicillin-susceptible and -resistant S. aureus isolates and S. aureus isolates with elevated vancomycin MICs (≥1 μg/mL). The data presented here are aimed to update the literature and better inform clinicians and clinical microbiologists about the revised telavancin MICs, as well as the corresponding clinical and microbiological cure rates for cSSSI patients.