Macrolide susceptibility and beta-lactamase production among haemophilus influenzae isolates in the United States, 1996-1997.
In 1996 and 1997, 68 hospital laboratories throughout the United States determined the beta-lactamase production and susceptibility to macrolides of 1,998 isolates of Haemophilus influenzae obtained from patients with community-acquired respiratory tract infections. The MICs at which 90% of the isolates are inhibited of azithromycin, erythromycin, and clarithromycin were 4, 8, and 16 microgram/ml, respectively. By National Committee for Clinical Laboratory Standards interpretive criteria, 99 and 78% of the isolates were susceptible to azithromycin and clarithromycin, respectively. The prevalence of beta-lactamase production was 32%.
Hogan
P A
PA
U.S. Pharmaceuticals Group, Pfizer Inc., New York, New York 10017, USA. hoganp@pfizer.com
Sheehan
D J
DJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D017291:Clarithromycin / Q000494:pharmacology; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D014481:United States; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D017963:Azithromycin; D001618:beta-Lactamases; D017291:Clarithromycin