Comparison of Wilkins-Chalgren medium supplemented with nicotinamide adenine dinucleotide and Haemophilus test medium for susceptibility testing of clinical Haemophilus isolates.
Haemophilus test medium (HTM) was compared with Wilkins-Chalgren agar (WCA; supplemented with 15 micrograms/ml nicotinamide adenine dinucleotide (NAD)) for antibiotic susceptibility testing of 74 clinical isolates of Haemophilus influenzae and Haemophilus parainfluenzae. The Bauer-Kirby agar disk diffusion method and the agar dilution procedure were the two tests employed. WCA + NAD and HTM yielded comparable results for the following antimicrobial drugs and drug combinations: ampicillin, amoxicillin plus clavulanic acid, ampicillin plus sulbactam, cefotaxime, cefuroxime, chloramphenicol, ciprofloxacin, and doxycycline. However, WCA + NAD slightly antagonized rifampin. Co-trimoxazole was significantly antagonized by WCA + NAD. WCA + NAD was much simpler with regard to in-house preparation, and WCA plates could be supplemented with NAD following pouring, solidification and storage of the plates simply by surface spreading the required amount of NAD with a glass spatula, thus adding considerably to laboratory flexibility. It is suggested that additional laboratories comparatively and critically examine WCA + NAD medium for antibiotic susceptibility testing of clinical Haemophilus isolates.
Institut für Medizinische Mikrobiologie und Hygiene, Universität des Saarlandes, Homburg/Saar, Germany.
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Traub
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Leonhard
D003470:Culture Media; D006190:Haemophilus / Q000187:drug effects*; D006193:Haemophilus influenzae / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009243:NAD / Q000494:pharmacology*
D003470:Culture Media; D009243:NAD