2002 Volume 76 Issue 3 Pages 167-173
To clear the route of STEC (Shiga toxin-producing Escherichia coli) infection to humans, we examined the serotype, Shiga toxin genotype and eae gene of STEC strains from humans and various animals. The most predominant serotype originated from humans was O157: H7, followed by O26: H 11, and other serotypes were O91: H21, O103: H2, O111: NM, O121: H19, etc. The eae gene was found in 79 of 93 strains from human origin. The serotypes of STEC from cattle were significant by similar to that of STEC from humans. The eae gene was found in 44 of 87 strains from cattle. Shiga toxin genotypes possessed O157 strains from humans and cattle, were divided into six groups, stx1, stx2, stx2c, stx1+stx2, stx1+stx2c and stx2+stx2c. Moreover, frequency rates of Shiga toxin genotypes of O157 were also similar to both human and cattle origins. The serotypes of STEC from sheep were also a little similar to that of STEC from humans. Seven of 8 strains from deer possessed stx 2d gene that the strains from humans seldom possessed, and none of the strains possessed eae gene. In STEC originated from swine, 15 of 25 strains were O139: H1 that Shiga toxin genotype was stx2e. It was thought that the sources of STEC infection to human are cattle and sheep, and deer and swine had little possibility to human STEC infection.
