Molecular Detection of Enteropathogenic and Shiga Toxin-Producing Escherichia coli and Their Antimicrobial Resistance Patterns Among Diarrheic Children in Addis Ababa, Ethiopia

Diarrheagenic Escherichia coli is among the primary causative organism of diarrhea in children less than five years of age. Increasing rate of antimicrobial resistance among E. coli is also a growing concern worldwide. The aim of this study was to determine the prevalence and antimicrobial resistance patterns of Enteropathogenic and Shiga Toxin-Producing Escherichia coli strains isolated from childhood diarrhea in selected primary health centers of Addis Ababa city. 200 stool samples from less than five years age children with diarrhea from both sexes (female=110 and male=90) were collected and inoculated on Eyosin Methyle Blue (EMB) and MacConkey agar (MA). E. coli was identified based on colony characteristics and standard biochemical tests and the molecular identification of pathogenic strains was performed using PCR targeting 3 virulence genes including stx1, stx2, eae for EPEC, EHEC and STEC detection. Among 94 E. coli isolates tested for the presence of Shiga Toxin producing Escherichia coli (STEC) virulence genes, 47 (50%) isolates carried stx genes (stx 1 and/or stx 2). The three E. coli strains, namely, STEC, EPEC and EHEC were detected at the rate 50%, 19% and 17%, respectively. Furthermore, the antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method . The majority of antibiotic resistance was found in tetracycline (81.9), and amoxicillin (97.9).In conclusion, diarrhea caused by E. coli pathotypes has been recognized as an important health problem. E. coli isolates demonstrated resistance to a number of antimicrobials. Future research efforts must target other virulence genes to cover all pathogenic E.coli strains and regular antimicrobial sensitivity testing should be encouraged to select effective antimicrobials and to reduce the burden of drug resistance.