Relationship between hygienic management practices of smallholder dairy farms and the distribution of Gram-negative mastitis pathogens along with their antibiogram in Bangladesh

A cross-sectional study investigated the occurrence and antimicrobial resistance (AMR) of Escherichia coli and Klebsiella pneumoniae in dairy farms, and their association with knowledge, attitude, and practices (KAP) related to udder health, hygiene, and mastitis, and biosecurity. A total of 206 samples (96 milk, 96 teat swabs, 14 floor swabs) were collected from 12 farms of Trishal and Shahjadpur upazilas. Milk samples were screened for subclinical mastitis (SCM) using BAU Mastitis Test, bacterial identification was performed using culture-based and molecular methods. Antimicrobial susceptibility test was performed by disk diffusion method, and associations were analyzed using binomial logistic regression. Overall, the occurrence of E. coli and K. pneumoniae was 20.9% and 27.7%, respectively, with 46.9% of quarters testing SCM positive. AMR patterns revealed that E. coli showed the highest resistance to ampicillin (41.9%), while K. pneumoniae exhibited high resistance to ampicillin (64.9%) and amoxicillin-clavulanic acid (49.1%). Multidrug resistance (MDR) was observed in 30.2% of E. coli and 42.1% of K. pneumoniae isolates. No predominant MDR pattern was observed for E. coli, whereas K. pneumoniae most frequently showed P-BLI-FPI-Ceph (n = 5) and P-BLI-FPI (n = 5) patterns. Binomial logistic regression analysis revealed that practice score, biosecurity perception score, KAP total score, and grand score were significantly associated with E. coli positivity, while only biosecurity perception score was significantly associated with K. pneumoniae positivity. These findings indicate that without concurrent antimicrobial stewardship and integrated herd health management, knowledge and self-reported practices might not be enough to reduce environmental mastitis pathogens.