Aeromonas cytotonic enterotoxin cross reactive with cholera toxin

Isolation by affinity chromatography from crude culture filtrate of Aeromonas sobria of protein that cross reacted with cholera toxin (CT) revealed a toxin that produced fluid accumulation in rat ileal loops and in infant mice and caused rounding of Y1 adrenal cells. All these activities were neutralised by antiserum to CT. There was no haemolytic or cytotoxic activity associated with this CT-cross reactive cytotonic enterotoxin. CT-cross reactive material detected in enzyme linked immunosorbent assay (ELISA) was produced by 25% of Aeromonas isolates from faeces of children with or without diarrhoea-26% of A. sobria, 20.0% of A. hydrophila and 24% of A. caviae tested gave positive ELISA results. Most strains that produced this cytotonic enterotoxin but no cytotoxic enterotoxin were isolated from children without diarrhoea. Toxin preparations from Aeromonas spp. that completely inhibited adenosine-5'-diphosphate-induced platelet aggregation, an effect related to elevation of intracellular cAMP, were, with one exception, cross reactive with CT in ELISA.