Enterotoxigenicity of clinical isolates of non-O1 Vibrio cholerae.

Whole cultures, but not culture supernatant fluids, of 21 isolates of non-O1 V. cholerae from patients with diarrhea were shown to induce positive fluid accumulation in infant mice. CHO cell assays demonstrated the elaboration of heat-labile cytotonic, cytotoxic or both factors from most isolates when grown under optimal culture conditions. These factors were not neutralized by anti-cholera toxin serum. Also genetic studies performed on 9 vibrio isolates using a DNA hybridization probe failed to detect gene sequences homologous with cholera toxin. ELISA assays recognized six isolates which produced a cell-associated substance which immunologically cross-reacted with cholera toxin. Enzymatic profiles of the vibrio isolates did not correlate with the production of any toxic factor. The results indicate that mainly heat-labile and cell-associated cytotonic and cytotoxic factors appear to influence the enterotoxigenic potential of this heterogenous group of non-O1 vibrios.