Comparative in vitro activity of ertapenem against bacterial pathogens isolated from patients with lower respiratory tract infections

This study compared the in vitro activity of ertapenem, ceftriaxone, cefepime, ciprofloxacin and amoxicillin-clavulanate against 381 aerobic and facultative bacterial pathogens isolated from 320 patients with acute bacterial exacerbation of chronic bronchitis or community-acquired pneumonia. Streptococcus pneumoniae and Haemophilus influenzae accounted for 54.6% of the isolates. The ertapenem MIC was ≤2 mg/L for 98.4% of isolates and ≥8 mg/L for 1.0% (all methicillin-resistant Staphylococcus aureus). Ertapenem had the most potent activity against Enterobacteriaceae, Moraxella catarrhalis, and methicillin-susceptible S. aureus, and its activity against H. influenzae and H. parainfluenzae, all strains of which were susceptible, was not altered by β-lactamase production. Only one S. pneumoniae strain, a penicillin-resistant isolate, was resistant to ertapenem. Ertapenem was highly active in vitro against pyogenic bacteria recovered from patients with community-acquired lower respiratory tract infections.