Reproducibility of disc susceptibility tests with Haemophilus influenzae.
Triplicate susceptibility tests were performed in each of three laboratories with 45 strains of Haemophilus influenzae and a single lot of Haemophilus test medium (HTM) agar plates. Using clarithromycin, erythromycin and chloramphenicol discs. zone sizes varied over ranges averaging only 4.3-5.8 mm. Ampicillin zone sizes were more variable, especially when beta-lactamase-producing strains were being tested, but the latter strains were consistently categorized as being resistant. A 94% interpretive consistency was observed with the two macrolides.
Barry
A L
AL
Clinical Microbiology Institute, Tualatin, Oregon 97062.
Jorgensen
J H
JH
Hardy
D J
DJ
D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D006193:Haemophilus influenzae / Q000187:drug effects*; D018942:Macrolides; D008826:Microbial Sensitivity Tests / Q000295:instrumentation; D015203:Reproducibility of Results
D000900:Anti-Bacterial Agents; D018942:Macrolides; D000667:Ampicillin