Selective growth of thermostable direct hemolysin-producing Vibrio parahaemolyticus in the alimentary tract of a gastropod, Clithon retropictus, at a selected estuary in Japan

Thermostable direct hemolysin (TDH)-producing Vibrio parahaemolyticus increased in cell number in the alimentary tract of a gastropod, Clithon retropictus, from an undetectable level in July to 2.0 x 10(3)/g in September 1991 at the Sada estuary in the southern part of Japan. It was not detected in microalgae. foods of the gastropod, at the estuary or muddy sediments at a neighboring fishing port. The strain was not detected at two estuaries and two fishing ports ecologically separated from the Sada estuary. Serotypes of the isolated strains were different from those registered as clinical isolates. Our results confirm that TDH-producing V. parahaemolyticus grows selectively in the gastropod at some estuaries in Japan.