Production of cytotoxins and enterotoxins by strains of Shigella and Salmonella isolated from children with bloody diarrhea.

The role of toxins in the pathogenesis of bloody diarrhea caused by Shigella and Salmonella isolated from children with bloody diarrhea was studied for production of toxins active on cells in culture and in rat intestinal loops. Human epithelial cells from colon carcinoma (HT-29), Chinese hamster ovary cells (CHO) and kidney fibroblast from rhesus monkey (Vero) were used to detect cytotoxins. On HT-29 almost 50% of the Shigella and about 20% of the Salmonella strains caused rounding of cells; on CHO over 50% of Salmonella and 20% of Shigella strains caused elongation of cells, some strains caused also rounding of these cells whereas on Vero over 60% of Salmonella and 40% of Shigella strains caused rounding of cells. Cytotoxicity on Vero and CHO cells was strongly inhibited with cholera toxin antiserum, whereas that on HT-29 was inhibited with C. difficile toxin B antiserum. Cytotonic activity on CHO cells and rounding on Vero cells seem to be suitable models to detect toxins cross-reacting with cholera toxin. Both species, Shigella and Salmonella, produce cytotoxins and enterotoxins which could play a role in intestinal disease.