Failure of the Vitek AutoMicrobic system to detect beta-lactam resistance in Aeromonas species.
The ability of the Vitek AutoMicrobic system (AMS; Vitek, Inc., Hazelwood, MO) and disk-diffusion method to detect beta-lactam resistance was assessed with 25 strains from four species of Aeromonas. A very major error was indicated when a strain was shown to be susceptible by the AMS or disk-diffusion method but resistant by the agar dilution method. The rates for very major errors for disk diffusion and the AMS were 0% and 43%, respectively. The beta-lactam agents and numbers of very major errors for the AMS were as follows: ticarcillin, 17; mezlocillin, 3; piperacillin, 4; cephalothin, 9; cefazolin, 3; cefoxitin, 1; cefotetan, 2; and cefuroxime, 1. Thus, these data suggest that the AMS currently is not reliable for testing the resistance of Aeromonas to beta-lactam agents.
Department of Medical Microbiology, Creighton University School of Medicine, Omaha, NE 68178.
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Schadow
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Giger
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Sanders
D000333:Aeromonas / Q000187:drug effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques / Q000295:instrumentation*; D004352:Drug Resistance, Microbial; D008826:Microbial Sensitivity Tests; D015203:Reproducibility of Results; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams