Genomic features of Escherichia coli isolated from Sonali chicken meat in Bangladesh

Antimicrobial resistance (AMR) in E. coli is a critical public health challenge, particularly in regions with unregulated antimicrobial usage in poultry production. Sonali chickens, a crossbreed favored in Bangladesh for their resilience and meat quality, have been underrepresented in AMR surveillance despite their economic and dietary importance. This study presents comprehensive genomic and phenotypic analysis of multidrug-resistant (MDR) E. coli isolated from Sonali chicken meat sold at live bird markets (LBMs) in Chattogram. A total of 50 samples were screened, with 74% (37/50) yielding an MDR E. coli, and 26 isolates were selected for whole-genome sequencing (WGS) Phenotypic results revealed extensive resistance to tetracyclines, sulfonamides, and ß-lactams, corroborated by genotypic detection of a variety of AMR genes, most notably tet(A), sul1, sul2, blaTEM-1B, and the rare but clinically significant gene tet(X4)—detected here for the first time in Sonali chicken–derived E. coli in Bangladesh. The results emphasize the urgent need for integrated, One Health–aligned surveillance, strict antimicrobial stewardship, and improved biosecurity across Bangladesh's poultry sector to mitigate zoonotic and public health risks posed by MDR E. coli.