Molecular Identification and Antibiotic Resistance of Shigatoxigenic Escherichia Coli Strains in Children under 5 with Diarrhea in Yasuj, Iran

Shigatoxigenic Escherichia coli (E. coli) strain is one of the most important causes of diarrhea, hemorrhagic colitis, and haemolytic uremic syndrome. The aim of this study was to survey the prevalence of shigatoxigenic strains and virulence genes in children of the age of under 5-years in Yasuj, Iran. This cross-sectional study was performed on 300 stool samples taken from children of the age of under 5-years with diarrhea in Yasuj. After initial identification of E. coli strains by culture and biochemical tests, shiga toxigenic Escherichia coli (STEC) genes such as eaeA, stx1 and stx2 detected by multiplex polymerase chain reaction (PCR) technique and antibiotic susceptibility of isolates was evaluated using disc diffusion method under the guidelines of Clinical and Laboratory Standards Institute (CLSI). Out of the samples, 104 (34.7%) STEC genes were separated. Out of considered virulence genes, 14 cases (13.46%) had stx1, 31 cases (29.81%) stx2, 9 cases (8.65%) genotype stx1-stx2, 12 cases (11.54%) eaeA-stx1, 25 cases (24.04%) eaeA-stx2 and 13 cases (12.5%) had third eaeA-stx1-stx2 genes. Antibiotic susceptibility test showed that the most susceptible antibiotic was imipenem for STEC; the most resistant antibiotic was ceftizoxime. Results showed that STEC strains have high prevalence in our study area. Therefore, hospital-wide surveillance using molecular techniques should be proposed in other regions of our country.