PCR analysis of pathogenic isolates. The presence of the specific virulence genes: eae gene (A), Aeromonas spp. specific gene (B), Vibrio cholerae specific sodB gene (C), and STEC specific stx1 gene (D). For positive controls, template DNA from EPEC ATCC 13706 (A), Aeromonas ATCC 7966 (B), Vibrio cholerae O1 ATCC 1966 (C), and Shigella flexineri strains (D) were used. M: Marker.