The impact of physico-chemical stress on the toxigenicity of Vibrio cholerae.

The expression of toxigenicity by Vibrio cholerae, before and after exposure to various conditions of salinity, pH and cation composition and concentration, has been measured. Exposure to these conditions did not select for hyper- or hypo-toxigenic strains. This suggests that toxigenic V. cholerae O1 are unlikely to lose their toxigenicity when exposed to environmental stress and that V. cholerae toxin production is not a response to the stresses included in this study. These results are consistent with an aquatic reservoir for toxigenic V. cholerae O1.