Identification of enterotoxigenic Escherichia coli strains in children under 2 years of age by real-time PCR in Shiraz

Enterotoxigenic strains of E. coli (ETEC) form the second largest group of diarrheagenic E. coli and are responsible for more than 25% of infantile diseases. The purpose of this study is to assess the prevalence of ETEC strains and their virulence genes in children less than 2 years of age in Shiraz. This was a cross-sectional study. 285 stool samples were taken from children under 2 years of age with diarrhea in Shiraz. First، E. coli strains were isolated using standard biochemical tests. Then، prevalence of ETEC strains and presence of st and lt genes were evaluated using real-time PCR. Antibiotic susceptibility of the isolates was evaluated by using disc diffusion method. 49 (17%) diarrheagenic E. coli strains were isolated، 7 cases (14/3%) belonged to ETEC strain. Among isolated ETEC strains، 4 (57. 14%) had lt، 1 (14. 29%) had stIa and 2 strains (28. 57%) had both lt and stIa genes. All ETEC strains were susceptible to chloramphenicol، amikacin and nitrofurantoin، but showed resistance to penicillin and macrolides. The results showed high prevalence of ETEC strains in our study area. We recommend hospital-wide surveillance by using molecular techniques to estimate the prevalence of this pathotype in other regions of our country.