Cytotoxicity of Vibrio parahaemolyticus in HeLa cell culture

In an investigation of the effect of Vibrio parahaemolyticus on epithelial cells in vitro, HeLa cells in slide culture chambers were inoculated with washed bacteria and several bacterial preparations. Preparations tested included live and heat-killed whole cells, unconcentrated culture filtrates, whole-cell lysates and their supernatant fluids, and supernatant fluids taken from HeLa cell monolayers previously inoculated with live bacteria. Slide cultures were evaluated at 3 and 5 hr by light microscopy and, in a few instances, by electron microscopy (live preparations) or at 24 hr by light microscopy (nonviable preparations). Live V. parahaemolyticus had a rapid cytotoxic effect that did not appear to be due to cellular invasion. The nonviable preparations had no effect on HeLa cells. The results demonstrate that V. parahaemolyticus is rapidly cytotoxic to epithelial cells in vitro and suggest that the presence of live organisms may be required for its enteropathogenicity.