In vitro activity of second and third generation cephalosporins against ampicillin susceptible and resistant haemophilus influenzae.
One hundred seventy-five clinical isolates of Haemophilus influenzae (including 74 beta-lactamase-producing strains) were examined for susceptibility to ampicillin, cefonicid, cefamandole, cefuroxime and cefotaxime. Cefonicid and cefamandole exhibited similar activity against ampicillin-susceptible strains (MIC90 = 0.2 mg/l for both antibiotics); cefuroxime was slightly less active (MIC90 = 0.01 mg/l). However, cefonicid, cefuroxime and cefotaxime were all more active against beta-lactamase-producing H. influenzae than cefamandole (MIC90 = 1.0 mg/l for cefonicid, MIC90 = 2.0 mg/l for cefuroxime, MIC90 = 0.01 mg/l for cefotaxime, MIC90 = 5.0 mg/l for cefamandole). One hundred twenty-five of the 175 isolates were also tested for susceptibility to cefonicid and cefamandole by disc diffusion technique and a plot of zone diameter vs. MIC was analyzed for the beta-lactamase-producing strains.
Burns
J L
JL
Division of Infectious Disease, Children's Hospital and Medical Center, Seattle, WA 98105.
Wong
K
K
Smith
A L
AL
D000667:Ampicillin / Q000494:pharmacology*; D000668:Ampicillin Resistance; D002511:Cephalosporins / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology; D001618:beta-Lactamases / Q000096:biosynthesis
D002511:Cephalosporins; D000667:Ampicillin; D001618:beta-Lactamases