Prevalence, Molecular Characterization and Antibiotic Susceptibility Pattern of Enteropathogenic Escherichia coli (EPEC) Strains Associated with Pediatric Diarrhoea in Abuja, Nigeria

Abstract

Aim: To determine the prevalence, molecular characteristics, and antibiotic susceptibility pattern of Enteropathogenic Escherichia coli (EPEC) strains isolated from children under five years of age presenting with acute diarrhoea in Abuja, Nigeria, and to evaluate the utility of combining serotyping with molecular diagnostics in EPEC identification. Study Design: Cross-sectional descriptive study. Place and Duration of Study: Abuja Municipal Area Council (AMAC), Federal Capital Territory, Abuja, Nigeria. Garki Hospital, Federal Medical Center, Abuja and National Hospital, Abuja between March 2022 and February 2023. Methodology: A total of 200 faecal samples were collected from pediatric patients (aged <5 years) with acute diarrhoea. E. coli was isolated using standard biochemical techniques. Confirmed isolates were serotyped with polyvalent and monovalent EPEC antisera. Molecular identification of the eaeA (intimin) and bfpA (bundle-forming pilus) virulence genes was carried out using polymerase chain reaction (PCR). Isolates were classified as typical EPEC (positive for both genes) or atypical EPEC (positive for eaeA only). Antimicrobial susceptibility testing was performed using the disc diffusion method for commonly used antibiotics. Results: Of the 200 stool samples analyzed, 19 (9.5%) were confirmed as EPEC. The most frequently detected serotype was O55:K59 (B5). Molecular analysis revealed that 5 isolates (26.3%) were positive for bfpA and 1 (5.2%) for both eaeA and bfpA genes, indicating a predominance of atypical EPEC strains. The remaining isolates lacked both virulence genes, suggesting the limitations of serotyping alone. Antimicrobial susceptibility testing showed 100% resistance to ampicillin, with high resistance to trimethoprim (89.5%) and tetracycline (84.2%). Ciprofloxacin, ceftazidime, and ceftriaxone exhibited the highest effectiveness. Multidrug resistance was observed in 26.3% of isolates. Conclusion: Atypical EPEC strains are more prevalent than typical EPEC in children with diarrhoea in Abuja. Combining molecular diagnostics with serotyping enhances detection accuracy. The high rate of antibiotic resistance, including multidrug resistance, underscores the need for routine surveillance to guide effective treatment and public health interventions.