Empirical Analysis of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Community and Hospital Settings Across Ogun and Oyo States

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are a globally critical antimicrobial resistance threat, yet comparative data between community and hospital reservoirs in South West Nigeria remain limited. This study empirically analyses ESBL-producing Enterobacteriaceae from clinical and community sources across Ogun and Oyo States, comparing resistance gene profiles and plasmid-mediated transmission patterns. Clinical isolates were collected from hospitals in Abeokuta and Ibadan, while community isolates were sourced from healthy volunteers, livestock faeces, and vegetable wash water. Isolates were characterised by cultural, biochemical, and ESBL phenotypic methods including double disk synergy and combined disk confirmatory tests. PCR was used to detect blaTEM, blaSHV, and blaCTX-M resistance genes. A total of 210 Enterobacteriaceae were analysed, of which 41 percent were ESBL-positive. CTX-M type enzymes predominated in both hospital and community isolates, establishing a shared genetic reservoir. Community isolates showed comparable ESBL prevalence (36 percent) to hospital isolates (45 percent), indicating significant community dissemination. Conjugation experiments confirmed horizontal gene transfer of ESBL plasmids between community and clinical strains. The study provides empirical evidence that Nigerian communities serve as active ESBL reservoirs, arguing for One Health approaches to AMR surveillance integrating human, animal, and environmental sampling in Ogun and Oyo States. Keywords: ESBL, Enterobacteriaceae, antimicrobial resistance, One Health, South West Nigeria