ENTEROPATHOGENICITY OF AEROMONAS-JANDAEI AND A-TROTA

An experimental study of five isolates of Aeromonas jandaei and 12 of A. trota was carried out to examine if they produced an enterotoxic su bstance, and if so, to characterise that factor and to see if it cause d any mucosal damage. Only two of the A. trota strains caused fluid ac cumulation in the initial rabbit ileal loop (RIL) tests. The remaining strains did so only after one to five sequential passages through RIL s and once they caused a secretory response they showed a gradual enha ncement of fluid outpouring after each subsequent passage. Inocula of similar to 1 x 10(5) viable cells and 0.25 ml of culture filtrate caus ed fluid accumulations comparable to those of toxigenic V. choler ne 5 69B. The enterotoxic factors of both organisms were inactivated when h eld at 56 degrees C for 20 min or 65 degrees C for 10 min and showed b iological activity over a wide range of pH. The only histopathological change observed in the ileal loop was depletion of mucus from the gob let cells. These data thus indicate that strains of A. jandaei and A. trota may produce a heat-labile and pH-stable diarrhoeagenic substance that causes little or no damage to the intestinal mucosa, like that o f other known heat-labile enterotoxins.