Extended-spectrum β-lactamase-producing Escherichia coli in chickens: prevalence and genetic diversity: a systematic review and meta-analaysis

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is an important antimicrobial-resistant pathogen in poultry that threatens animal health, food safety and public health. This study reviewed the global prevalence and genetic diversity of ESBL-EC in chickens and compared prevalence across continents and chicken production systems.2. A meta-analysis was conducted following PRISMA guidelines. Forty-five studies published between 2014 and 2023, comprising 13 761 E. coli isolates from broiler, layer and mixed-breed chickens, were included. Random-effects meta-analysis estimated pooled prevalence, while subgroup and meta-regression analyses explored heterogeneity. Any ESBL-associated genes were summarised.3. The pooled prevalence of ESBL-EC in chickens was 31.44% (95% CI: 23.81–39.07). Prevalence was highest in Asia (36.22%) and Africa (26.66%) and lowest in North America (5.20%). Broiler chickens showed substantially higher prevalence (33.13%) than layer chickens (8.79%).4. Genetic analysis demonstrated that CTX-M-type β-lactamases predominated, with blaCTX-M as the most frequently detected ESBL gene, followed by blaTEM and blaSHV. The higher prevalence in broiler chickens reflected intensive production systems, shorter production life spans and greater antimicrobial exposure. The lower prevalence in layer chickens reflects longer production life spans and comparatively lower antimicrobial usage.5. The resistant E. coli ESBL strain is widely distributed in poultry, particularly in production systems and in Asia and Africa. Strengthened antimicrobial stewardship, improved farm biosecurity and integrated ‘One Health’ surveillance are required to reduce the dissemination of ESBL-producingE. coli and mitigate associated public health risks.