Comparative In Vitro Activity of Telithromycin and β-Lactam Antimicrobials Against Bacterial Pathogens from Community-Acquired Respiratory Tract Infections: Data from the First Year of PROTEKT (1999-2000)

Abstract

The In Vitro activity of telithromycin, a new ketolide, was compared with β-lactam antimicrobials against pathogens commonly associated with community-acquired respiratory tract infections. These pathogens were collected during 1999-2000 as part of the ongoing PROTEKT surveillance study. Globally, penicillin non-susceptibility among Streptococcus pneumoniae (n=3362) was 36.3%, ranging from 21.5% (Australasia) to 68.0% (Far East). Telithromycin showed higher potency (MIC₉₀ 0.12 mg/L) than β-lactams against S. pneumoniae; 99.9% of all and 99.6% of multi-resistant isolates were susceptible to telithromycin. Among Streptococcus pyogenes isolates (n=1485), 100% were susceptible to β-lactams, and the telithromycin MIC₅₀ and MIC₉₀ were both 0.015 mg/L. Among Haemophilus influenzae (n=2948), 16.6% produced β-lactamase, which reduced the activity of ampicillin, cefaclor and cefprozil. 99.9% of H. influenzae were susceptible to telithromycin and the MIC range for M. catarrhalis was 0.004-0.5 mg/L. The first year results of PROTEKT confirmed high potency for telithromycin against common respiratory tract pathogens, including β-lactam-resistant strains.