Migratory Birds Facilitate the Spread of Multidrug-Resistant Pathogenic Escherichia coli in Tanguar Haor of Bangladesh.

This study investigated the occurrence of pathogenic and multidrug-resistant (MDR) Escherichia coli in migratory birds inhabiting wetland habitats. A total of 167 freshly voided faecal samples were collected from migratory birds during the winters of 2023 and 2024. Isolation and identification of E. coli were performed using standard cultural and molecular techniques. Antimicrobial susceptibility testing was performed against 19 antibiotics, followed by the detection of resistance genes. Overall, the E. coli detection rate was 68.62% and 46.15% in 2023 and 2024, respectively. Multiple diarrheagenic E. coli pathotypes (ETEC, EAEC, EHEC, EPEC and EIEC) were identified, where the isolates from 2023 showed greater diversity. Most of the E. coli isolates were identified as MDR, with MDR patterns being more frequent in 2024. Resistance genes associated with tetracycline, β-lactam and aminoglycoside antibiotics, where tetB, tetO, tetC, blaCTX, blaSHV and blaTEM were more prevalent than the rest of the genes. Our findings indicate that migratory birds are potential mobile reservoirs and disseminators of MDR E. coli within the wetland ecosystems, warranting coordinated and sustained One Health surveillance across environmental, wildlife and public health.