In vitro activity of tigecycline against 3989 Gram-negative and Gram-positive clinical isolates from the United States Tigecycline Evaluation and Surveillance Trial (TEST Program; 2004)

Abstract

The Tigecycline Evaluation and Surveillance Trial (TEST Program) determined the in vitro activity of tigecycline over a large population of organisms from geographically diverse sites. Tigecycline was compared to amikacin, ampicillin, amoxicillin/clavulanic acid, imipenem, cefepime, ceftazidime, ceftriaxone, levofloxacin, minocycline, piperacillin/tazobactam, linezolid, penicillin, and vancomycin against 3989 commonly encountered clinical Gram-negative and Gram-positive pathogens collected from sites in the United States during 2004. The tigecycline activity was equivalent to imipenem against Enterobacteriaceae. Tigecycline inhibited extended-spectrum β-lactamase and AmpC phenotypes at MIC 90 values (minimum inhibitory concentration) of ≤2 μg/mL. In vitro results for tigecycline were similar to other broad-spectrum antimicrobial agents against nonfermenters with MIC 90 results of 2 μg/mL against Acinetobacter spp. and >16 μg/mL against Pseudomonas aeruginosa. Tigecycline demonstrated potent activity against Staphylococcus aureus (MIC 90, 0.25 μg/mL) and enterococci (MIC 90, 0.12 μg/mL) regardless of methicillin or vancomycin susceptibility. Tigecycline MIC values were unaffected by penicillin nonsusceptibility and β-lactamase production among fastidious respiratory pathogens ( Streptococcus pneumoniae [MIC 90, 0.5 μg/mL] and Haemophilus influenzae [MIC 90, 0.25 μg/mL]). Tigecycline offers excellent activity against most of the commonly encountered nosocomial and community-acquired bacterial pathogens.