A comparison of different culture media for the membrane filter quantification of Aeromonas in water

A comparative assessment of culture media for the membrane filter enumerati on of Aeromonas spp. in water was performed, testing the effects of differe nt incubation conditions (aerobic and anaerobic), temperatures (30 and 37 d egrees C) and times (24 and 48 h). Different water samples seeded with test suspensions of Aeromonas spp., fecal material or raw sewage were examined. Results indicate clearly that plates should be incubated aerobically at 30 degrees C for 24 h. If the bacterial contamination is likely to be low, th e use of most sensitive culture media, such as SAA, mA, ADA or PADE Agar, i s recommended. By contrast, samples with an expected high level of backgrou nd microbial flora should be analysed through more selective media, such as MIX Agar. However, the low selectivity of all media tested and the high li kelihood of false negatives based upon the macroscopic examination of colon ies means that further research directed to the development of more efficie nt media is needed.