Role of biosecurity practices in antimicrobial use on commercial poultry farms: One health implications for AMR mitigation in Bangladesh.

The indiscriminate use of antimicrobials in food-producing animals is a major contributor to antimicrobial resistance (AMR), a global One Health challenge that threatens the interconnected health of humans, animals, and ecosystems. Hence, this study conducted to assess the association between farm-level biosecurity practices and antimicrobial use in commercial poultry farms in Bangladesh. A cross-sectional study was conducted on 331 poultry farms (broiler: 113, layer: 103, Sonali: 115) across six districts from September to December 2021. A directed acyclic graph informed variable selection and generalized linear models (GLM) and least absolute shrinkage and selection operator (LASSO) regression were used to identify factors associated with antimicrobial use. Overall, 27.8% of farms reported antibiotic use on the day of the interview, and 49.2% had used antibiotics in the preceding 14 days. Antimicrobial use was significantly higher in rural farms and those with dirt floors or floor-based rearing systems. Higher odds of antimicrobial use were also linked to farmer education level, proximity to recent avian influenza outbreaks, unrestricted access of wild animal, and nearby crow roost. Conversely, farms implementing stronger biosecurity including isolating sick birds, and farms rearing layer birds and maintaining improved infrastructure reported significantly lower antibiotic use. These findings indicate that farm infrastructure, wildlife interfaces and hygiene practices are important correlates of antimicrobial use. Strengthening farm-level biosecurity, regulating antimicrobial access, and expanding veterinary extension services, especially in rural areas are critical to reduce antibiotic dependency and mitigating AMR risks. Establishing a national AMR surveillance framework that links animal, environmental, and human health sectors is essential to monitor resistance patterns and guide targeted policy interventions.