Isolation of Escherichia coli O157 from pigs with colibacillosis in Canada and the United States.

Cultures of Escherichia coli isolated from colibacillosis in pigs in Canada and the U.S.A. and previously identified as unclassified E. coli OX36 were found to belong to a new E. coli O group 157. Strains of E. coli V145, GIRI, C308 and V17 which had a weak relationship to E. coli O116 also were found to belong to O157. The increased incidence of E. coli O157 in colibacillosis of swine stresses the inclusion of this O group among those enteropathogenic for swine.