Fate of Vibrio cholerae O1 in seawater microcosms

Survival of Vibrio cholerae O1 ATCC 14035 in seawater was studied, employing laboratory microcosms of 3.5% salinity and transfer of cells from growth media of different osmotic strengths. Cells previously grown in M9 mineral medium amended with 0.5 M sucrose showed a decrease of 2 log units in number of culturable cells, after exposure to seawater for 10-12 days, the number of culturable cells remaining unchanged during the next 50 days. When pregrown in M9 medium, or in M9 amended with 0.5 M NaCl, the number of culturable cells decreased 3 and 5 log units, respectively, then increased to the same concentration as cells grown in sucrose. Morphological changes were observed, depending on the medium employed. Results of the study showed that V. cholerae ATCC 14035 can remain in the culturable state in seawater for a relatively long time, i.e. sufficiently long to be carried by ocean currents to widely distant geographical locations.