Response of toxigenic<i>Vibrio cholerae</i>01 to physico-chemical stresses in aquatic environments

The survival and growth of toxigenic Vibrio cholerae 01 in water under various conditions of salinity, pH, temperature and cation composition and concentration were studied in an extensive series of laboratory experiments. Inter- and intra-strain variation in stress response (of 01 and non-01 strains) and the ability of V. cholerae to adapt to stressful environments were also studied. Toxigenic V. cholerae 01 were able to survive for at least 70 days at 25 degrees C in solutions of sea salt. The optimal salt concentration was 2.0% though all solutions in the range 0.25-3.0% gave good support. Substrains with enhanced capacity to persist at sub-optimal salinity (0.1%) were demonstrated. A great degree of inter-strain variation in stress response at low salinity…