Foodborne sources of antimicrobial-resistant Escherichia coli in community-acquired urinary tract infections in Bangladesh.

BACKGROUND

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec) causing urinary tract infections (UTI) are presumed to originate from poultry, but evidence from resource-limited settings is scarce.

METHODS

We conducted a prospective surveillance of UTI patients alongside food sampling within the same temporospatial context in Dhaka, Bangladesh (2016-2018). A total of 2297 food samples, including 970 poultry meat, 504 fresh produce, 334 fish, 327 eggs, and 162 beef were collected from 24 wet markets and tested for E. coli and ESBL-Ec. During the same period, 110 ESBL-Ec isolates were obtained from 394 UTI patients residing near these markets. Phylogroups of ESBL-Ec from both sources were determined, and representative isolates were subjected to whole-genome sequencing. Additionally, seven-day dietary recall interviews were conducted with 100 ESBL-Ec UTI patients and 200 age- and sex-matched controls.

RESULTS

Here we show that 87% (n = 1993) of food samples are positive for E. coli while 30% (n = 601) contain ESBL-Ec, predominantly in poultry meat (43%), followed by beef (36%), fish (24%), eggs (12%), and fresh produce (6%). Urinary ESBL-Ec isolates are dominated by phylogroup B2 (63%) and ST131 (56%), both absent in food. Poultry isolates show higher diversity compared to urinary isolates. ESBL-Ec ST648, ST38, ST10, ST457 occur in both sources, but core genome SNP analysis shows no clonal relatedness ( > 22 SNPs). Poultry consumption is not associated with ESBL-Ec UTI, although a seven-day recall may not capture prior colonization events.

CONCLUSION

Overall, UTI-causing ESBL-Ec are genetically distinct from poultry isolates, suggesting that poultry is unlikely to be a major source of UTI in this setting.