Genetic variations in Aeromonas hydrophila isolates from clinical and environmental sources in Thailand.

Aeromonas hydrophila, a widely distributed human pathogen causing a variety of diseases, can be isolated from clinical and environmental sources. Analysis in Thailand of 110 isolates of Aeromonas hydrophila by randomly amplified polymorphic DNA-PCR (RAPD-PCR) revealed one specific RAPD pattern group (G) that was associated only with strains from environmental sources. Cytotoxic activity, adhesion to epithelial cells and exoenzyme secretions of A. hydrophila were also investigated. A comparison of isolates with pattern group G with a set of isolates derived from human blood showed low induction of cytotoxicity from those with RAPD pattern group G suggesting low virulence of these strains.