Prevalence of Diarrheagenic Escherichia coli Pathotypes from Patients with Diarrhea by Multiplex Real-Time PCR Assay in South of Iran.

Background and Objectives: Diarrhea is an important cause of death among all ages and the most common cause of morbidity and mortality among children in developing countries. Different virotypes of diarrheagenic Escherichia coli (DEC) account as important enteric pathogens in human. The goal of this study is simultaneous identification of different virotypes of diarrheagenic Escherichia coli and evaluation of the prevalence of Enteropathogenic E. coli (EPEC), Enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC), Entero-invasive E. coli (EIEC), Entero-aggregative E. coli (EAEC) and Diffuse Adherent E. coli (DAEC) in patients with diarrhea in Shiraz using multiplex Real-time PCR technique. Materials and Methods: This cross-sectional descriptive study was done on 715 fecal samples obtained from patients with diarrhea in 2012 in Shiraz (Iran). After initial identification of E. coli strains by standard biochemical tests, simultaneous differentiation of six virotypes of diarrheagenic Escherichia coli and identification of pathogenic genes stx1, stx2, eaeA, st, lt, ipaH, aggR and daaD were performed by multiplex Real-time PCR combined with SYBR Green I. Results: A total of 715 stool samples were tested in which 11 (14.2%) were identified as contaminated with E. coli by biochemical tests. 29 STEC (28.71%), 26 EPEC (25.74%), 18 EIEC (17.82%), 15 ETEC (14.85%), 5 EAEC (4.95%), and 8 DACE (7.92) were identified using multiplex Real-Time PCR assay. Conclusion: In conclusion, our analysis indicated that DEC pathotypes may be considered as potential pathogens in Shiraz, southern Iran. Molecular analysis by multiplex Real-time PCR is a universal method for simultaneous identification of six virotypes of diarrheagenic Escherichia coli. This study suggests that DEC is one of the important pathogens that should be considered in the surveillance program of diarrheal diseases.