Risk-zone-stratified occurrence and antimicrobial resistance of E. coli and Salmonella spp. in ready-to-eat foods sold near elementary schools in urban Bangladesh

Ready-to-eat foods sold near schools may contribute to children’s exposure to enteric bacteria, particularly in urban settings where informal food vending occurs near wastewater, animal markets, slaughter-related activities, and poorly managed solid waste. This study assessed the prevalence and antimicrobial resistance profiles of Escherichia coli and Salmonella spp. in ready-to-eat foods sold near elementary schools in an urban area of Bangladesh, comparing school areas with different environmental risk conditions. A comparative cross-sectional study was conducted from November 2025 to February 2026 in urban area of Bangladesh. A total of 210 ready-to-eat food samples were collected from vendors within 200 m of 30 elementary schools, including 105 samples from high-risk school areas and 105 from low-risk areas. High-risk schools were located within 500 m of predefined potential contamination sources, while low-risk schools were at least 1.5 km away. E. coli and Salmonella spp. were isolated using culture-based methods and confirmed by polymerase chain reaction. Antimicrobial susceptibility was assessed using the Kirby–Bauer disk diffusion method. Prevalence estimates were calculated with 95% confidence intervals. Associations were examined using chi-square or Fisher’s exact tests and multivariable logistic regression with school-cluster-adjusted standard errors. Overall, 89 of 210 samples were contaminated with at least one target organism, giving a prevalence of 42.4%. E. coli was detected in 41 samples (19.5%), and Salmonella spp. was detected in 57 samples (27.1%). Contamination was higher in high-risk than low-risk areas for E. coli (34.3% vs. 4.8%), Salmonella spp. (41.0% vs. 13.3%), and any contamination (66.7% vs. 18.1%). In adjusted models, high-risk areas remained strongly associated with E. coli contamination, Salmonella contamination, and any contamination. All tested isolates were resistant to amoxicillin. Multidrug resistance was more frequent among Salmonella isolates than E. coli isolates. Ready-to-eat foods sold near elementary schools in this urban setting showed substantial contamination with E. coli and Salmonella spp., with higher contamination in environmentally high-risk school areas. These findings highlight the need for One Health food-safety surveillance integrating school health, municipal sanitation, animal-market hygiene, vendor practices, and AMR monitoring. Trial registration : Not applicable; this study did not involve a health care intervention or enrollment of human participants.