ESBL and Integron Profiles in Pediatric EPEC/STEC

Background: Diarrheagenic Escherichia coli (DEC) is a major cause of pediatric diarrhea, particularly in low- and middle-income countries. Antimicrobial resistance, including extended-spectrum β-lactamase (ESBL) production, further complicates clinical management. This study investigated DEC pathotypes, resistance patterns, ESBL prevalence and integron carriage among children with acute diarrhea in Mansoura, Egypt. Methods: A total of 120 children (median age 6 years; 50.8% male) presenting with acute diarrhea were enrolled. Clinical data were recorded, and stool samples were cultured for E. coli . Phenotypic antibiotic susceptibility testing, ESBL detection and polymerase chain reaction assays for DEC pathotypes and class I/II integrons were performed. Results: E. coli was isolated from 60 (50%) children. The predominant pathotype was Shiga toxin–producing E. coli (STEC, 46.7%), followed by typical enteropathogenic E. coli (tEPEC, 45%) and atypical EPEC (aEPEC, 8.3%). High resistance rates were observed for amoxicillin/clavulanic acid (85%), cefadroxil (60%) and ampicillin (58.3%). ESBL production was detected in 41.7% of isolates. Class I and II integrons were identified in 51.7% and 16.7% of isolates, respectively, with a strong association between both integrons in STEC and tEPEC ( P < 0.001). No significant association was found between integron carriage and ESBL production ( P = 0.34) or antibiotic resistance profiles. Conclusions: DEC is a significant cause of pediatric diarrhea in Egypt, with STEC and tEPEC predominating. The high prevalence of antimicrobial resistance, ESBL production and integron carriage underscores the urgent need for surveillance programs, antimicrobial stewardship and improved infection control to limit resistance dissemination in pediatric populations.