In vitro activity of telavancin and occurrence of vancomycin heteroresistance in isolates from patients enrolled in phase 3 clinical trials of hospital-acquired pneumonia.

In phase 3 studies of the efficacy of telavancin for the treatment of hospital-acquired pneumonia, 704 Gram-positive and 627 Gram-negative aerobic bacterial pathogens were obtained at baseline from 1503 patients. The majority of Gram-positive isolates (n = 650 [92%]) were Staphylococcus aureus, of which 410 (63%) were methicillin-resistant (MRSA). Of the MRSA isolates, 9.5% were identified as heterogeneous vancomycin-intermediate S. aureus. All Gram-positive isolates were inhibited by ≤1 μg/mL of telavancin.