Ampicillin-dextrin agar medium for the enumeration of Aeromonas species in water by membrane filtration |
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| Authors: | A H Havelaar M During J F M Versteegh |
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| Institution: | Laboratory of Water and Food Microbiology, National Institute of Public Health and Environmental Hygiene, PO Box 1, 3720 BA Bilthoven, The Netherlands |
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| Abstract: | Published selective media were evaluated for the isolation of Aeromonas spp. from environmental samples by membrane filtration. Satisfactory recoveries were obtained only with mA agar (Rippey & Cabelli) and dextrin-fuchsin-sulphite agar (Schubert), but neither was sufficiently selective. The positive aspects of these two media were combined in a new medium, ampicillin-dextrin agar. Recovery from pure cultures and environmental samples was optimal at an ampicillin concentration of 10 mg/l and incubation for 24 h at 30°C under aerobic conditions, and specificity was high (i.e. confirmation rate usually <90%, no false negative colonies encountered). The medium can also be used for isolation of Aeromonas spp. from sea water provided that the vibriostatic agent 0/129 is added at 50 mg/1. |
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