PATHOGENIC PROPERTIES OF •gENTEROPATHOGENIC•h ESCHERICHIA COLI FROM DIARRHEAL CHILDREN AND ADULTS

The •genteropathogenicity•h of Escherichia coli serotypes isolated from diarrheal adults and children was examined by three bioassay systems ; inoculation into guinea pig eyes, into ligated rabbit intestine, and to cultured HeLa S3 cells. The OK types, 0144:K ? (B), 0143:K ? (B), 0136:K78, 0124:K72, and 028a, c:K73, were isolated from the patients of dysentery-like symptoms and designat ed as Shigella-like group. These strains, except one old laboratory strain, were positive in the three bioassays causing keratoconjunctivitis in guinea pigs, dila tation of the rabbit intestinal segments, and intracellular multiplication within HeLa cells. On the other hand, the OK types, 026:K60, 044:K74, 055:K59, 0119:K69, 0126:K71, 0128:K67, 0146, K86, 086a : K61, and 086a : K62 were isolated from the patients of gastroenteritis symptoms and designated as Salmonella-like group. All the strains of this group were completely negative in the three bioassay systems. The ablity of Shigella-like E. coli to penetrate into the cells of intestinal epithelial lining was interpreted as the indispensable factor for establishment of the infection, as was the case with Shigella bacilli.