The occurrence of Aeromonas spp. in natural mineral water and well water.

The presence of motile Aeromonas spp. in natural mineral water (NMW) and drinking well water in the area of Lecce (Italy) was investigated. Aeromonas spp. were not detected in any of the 60 NMW samples either by the direct and enrichment method. From a total of 20 wells, five were found to contain Aeromonas species with cell number ranging from 26 to 1609 250 ml(-1). In two wells the presence of Aeromonas spp. was not associated to the presence of faecal indicators, i.e. coliforms and faecal coliforms. Sixty-five Aeromonas spp. strains isolated in this survey were identified at species level and some were examined for haemolysis, Voges Proskauer reaction, lysine decarboxylase and sorbitol fermentation, tests which had been previously shown to correlate with production of enterotoxin/cytotoxin. Isolates identified as A. hydrophila and A. sobria showed potentially virulent properties.