Development of a set of multiplex PCR assays for the simultaneous identification of enterotoxigenic, enteropathogenic, enterohemorrhagic and enteroinvasive Escherichia coli

Diarrheagenic E. coli comprise a diverse group of microorganisms responsibl e for gastrointestinal diseases in humans. On the basis of their virulence traits they are distinguished from the non-pathogenic E. coli and classifie d in several categories. Molecular methods represent the most reliable tech niques for distinguishing pathogenic from non-pathogenic E. coli and charac terising their pathogenic features. In this paper we report the development of a set of three multiplex PCR assays for the simultaneous and rapid iden tification of diarrheagenic E. coli belonging to ETEC, EPEC, EHEC and EIEC groups. Assay 1 utilizes primer pairs specific for genes coding for ST and LT toxins of ETEC, and for the E. coli beta -glucuronidase (uidA); assay 2 detects the presence of the eae and bfpA genes of EPEC, and assay 3 recogni zes sat and stx2 of EHEC, and ial of EIEC. This technique has been validate d on 190 E. coli isolated in Angola, Italy and Mozambique from feces of chi ldren with diarrhea. Results obtained with the set of multiplex PCR demonst rated 100% accordance with those obtained for the same isolates by PCR on s ingle target genes. The proposed set of multiplex PCRs is the first reporte d assay that allows the simultaneous characterization of the four categorie s of diarrheagenic E. coli.