DISTRIBUTION OF AEROMONAS-HYDROPHILA HYBRIDIZATION GROUPS AND THEIR VIRULENCE PROPERTIES IN AUSTRALASIAN CLINICAL AND ENVIRONMENTAL STRAINS

A total of 182 Aeromonas hydrophila strains isolated from environmenta l (food and water) and clinical (stool and other sources) samples take n in mainland Australia, Tasmania and New Zealand were assigned to one of three DNA/DNA hybridization groups (HGs) on the basis of biochemic al characteristics, and tested with regard to their ability to produce virulence factors. Strains from HG2 were rarely isolated; strains fro m HG1 were most commonly isolated from clinical sources; and strains f rom HG3 formed the majority of environmental strains. There was no cor relation of HG to geographic source. Strains from HG2 infrequently pro duced virulence factors. Strains from HG1 were more likely to produce virulence factors if they came from a clinical source. Overall, strain s from mainland Australia produced virulence factors more frequently t han those from Tasmania or New Zealand. Strains from HG1 may be of mor e clinical significance than strains from the other two HGs.