Relationship between enterotoxicity and multiple drug resistance in Aeromonas spp.

One hundred forty-seven isolates of Aeromonas spp., including 54 from diarrhoeal patients and 93 from the environmental sources, were examined for drug sensitivity and enterotoxin production. One hundred and fifteen (78%) isolates that included all A. hydrophila, 60% of A. sobria and 89% of A. caviae showed resistance to one or more antibiotic(s). Most (65%) of the resistant isolates caused fluid accumulation in rabbit ileal loops, of these 57% were A. hydrophila, 69% of A. sobria and 65% A. caviae, whereas only a few drug-sensitive isolates did so. Multiple drug-resistant isolates caused comparatively more fluid accumulation than the drug-sensitive isolates. Furthermore, significant difference of ileal fluid accumulation was observed with the increase in the number of resistance markers. This study suggests that there is some association between multiple drug resistance and enterotoxicity of Aeromonas strains, regardless of their source of isolation and species.