Journal of Antimicrobial Chemotherapy (1987) 20, 663-669
© 1987 The British Society for Antimicrobial Chemotherapy
research-article |
Comparative bactericidal activity of cefixime, carumonam, enoxacin and roxithromycin with those of other antibiotics against resistant Haemophilus influenzae including ß-lactam tolerant strains
Service d'Infectiologie, Le Centre Hospitalier de I'Université Laval, and Département de Microbiologie, Faculté de Médecine, Université Laval Quebec City, Canada GIV 4G2
accepted 3 May 1987
One hundred isolates of Haemophilus influenzae including 50 ß-lactamase producing, five ampicillin-resistant non-ß-lactamase producing and five ß-lactam tolerant strains were tested for susceptibility (MICs and MBCs) to ampicillin, aztreonam, carumonam, cefixime, cefaclor, cefamandole, cefotaxime, imipenem, enoxacin, ciprofloxacin, roxithromycin, erythromycin, chloramphenicol, and co-trimoxazole, by a microdilution broth method. Cefotaxime, enoxacin and ciprofloxacin with MIC90, and MBC90 of <0.03 mg/l) were the most active antimicrobial agents tested. Cefixime, carumonam, aztreonam, and co-trimoxazole (MIC90 and MBC90 <0.25 mg/l) showed good activity against most strains. Roxithromycin and erythromycin had limited antibacterial activity (MIC90, 8 and 4 mg/l respectively). There were no chloramphenicol-resistant strains. Five ß-lactamase-negative strains were resistant to ampicillin, cefaclor and cefamandole but susceptible to other ß-lactams tested. Different patterns of tolerance were observed: four of five tolerant strains were tolerant to ampicillin and cefamandole, three to cefixime, cefaclor and cefotaxime, one to aztreonam. One tolerant strain was a ß-lactamase producer. Two other strains were tolerant only to co-trimoxazole.