Abstract
Background:
Foodborne pathogens, particularly antibiotic-resistant strains, pose a significant threat to public health globally.

Aim:
To explore the emergence and spread of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in the food chain, focusing on broiler chickens in wet markets.

Methods:
Specimens were inoculated into TBX medium supplemented with cefotaxime 4 ug/ml for selective isolation of ESBL-producing E. coli. Phenotypic and genotypic characterization of the isolates was performed, including species detection using PCR for E. coli identification with specific primers targeting the gene and a double diffusion synergy test for ESBL identification.

Results:
A total of 262/305 (86%) samples were confirmed positive for ESBL-producing E. coli from broiler chickens and free-range chickens. blaCTX-M were mostly identified among ESBL-producing E. coli from broiler chickens (91%) or free-range chicken (100%), followed by blaTEM 20% and 23%, respectively. There were no identified blaSHV genes. Among 50 ESBL producers, E. coli (31; 17.4% from broiler chickens and 19; 22.6% from free-range chicken) were identified with a co-incidence of blaCTX-M and blaTEM.

Conclusion:
There is an increased prevalence of ESBL-producing E. coli in environmentally contaminated foods. Hygiene and antibiotic use regulations for poultry farms should be improved. ESBL genes among chickens are mainly blaCTX-M (94%), followed by blaTEM (21%), which has a lower incidence; no blaSHV was detected.

Key words: Antimicrobial resistance, Chicken, Escherichia coli, ESBL, Food chain, Infectious disease