Urbanization shapes multidrug resistance dynamics in livestock farms of Bangladesh

In low- and middle-income countries (LMICs), rapid urbanization focuses intense anthropogenic and ecological pressure that increases antimicrobial resistance (AMR) at the human-animal-environment interface. Urban livestock farms in Bangladesh are located close to hospitals, industrial areas and crowded human habitation, habitats conducive to the exchange/mixing of resistant or multidrug resistant organisms. This work aimed to assess the effect of urban ecological pressures on MDR dynamics among farm animals, within the framework of One Health. A cross-sectional study was performed among 40 cattle farms in three eco-diversified districts of Bangladesh (Dhaka, Barisal and Sylhet) viz. urban-20 and non-urban-20 areas. Three-hundred-sixteen bovine and environmental samples were tested for Escherichia coli , Klebsiella pneumoniae , Pseudomonas aeruginosa , and Enterococcus faecalis . Antimicrobial susceptibility testing followed CLSI guidelines 2024, Isolates and resistance genes were detected by PCR and vitek2 compact, and multiple antibiotic resistance index (MARI) was calculated. Multivariate logistic regression identified independent MDR predictors. MDR prevalence was significantly higher ( p < 0.001) in urban farms for E. coli (45.5%), K. pneumoniae (77.4%), and E. faecalis (86.9%), alongside significantly elevated MARI values, indicating strong antibiotic selection pressure. Significant differences in antimicrobial resistance gene carriage were observed between urban and non-urban isolates and varied by bacterial species. Urban K. pneumoniae isolates showed higher carriage of blaCTX-M , blaNDM-5 , blaOXA-48 , and blaOXA-1 , while blaNDM-5 and blaOXA-1 were also significantly more frequent among urban E. coli isolates. In contrast, blaCTX-M carriage among E. coli isolates did not differ significantly between urban and non-urban farms (72.7% vs. 65.1%, p = 0.25). In contrast, MDR P. aeruginosa and mcr-1 were predominantly associated with non-urban farms. Regression analysis identified proximity to public hospitals (OR 5.36), industrial zones (OR 4.13), and high antibiotic usage (OR 3.71) was associated with urban farms, whereas wild bird exposure (OR 17.65), poor hygiene (OR 4.40), and improper pharmaceutical waste disposal (OR 6.00) were significant predictors in non-urban systems. This study found a higher prevalence of MDR bacterial isolates in urban livestock farms than in rural farms in Bangladesh. Although the underlying factors were not directly investigated, the observed differences highlight the need for further studies to identify the drivers of antimicrobial resistance and support targeted One Health interventions.