Haemophilus influenzae and Moraxella catarrhalis from patients with community-acquired respiratory tract infections: Antimicrobial susceptibility patterns from the SENTRY Antimicrobial Surveillance Program (United States andCanada, 1997)

Between February and June of 1997, a targe number of community-acquired res piratory tract isolates of Haemophilus influenzae (n = 1,077) and Moraxella catarrhalis (n = 503) from 27 U.S. and 7 Canadian medical centers mere cha racterized as part of the SENTRY Antimicrobial Surveillance Program. Overal l prevalences of beta-lactamase production were 33.5% in H. influenzae and 92.2% in M. catarrhalis with no differences noted between isolates recovere d in the United States and those from Canada. Among a total of 21 different antimicrobial agents tested, including six cephalosporins, a beta-lactamas e inhibitor combination, three macrolides, tetracycline, trimethoprim-sulfa methoxazole (TMP-SMX), rifampin, chloramphenicol, five fluoroquinolones, an d quinupristin-dalfopristin, resistance rates of >5% with H. influenzae mer e observed only with cefaclor (12.8%) and TMP-SMX (16.2%).