Isolation, characterisation and biofilm-forming ability of Escherichia coli from postpartum dairy cows with endometritis

Postpartum uterine infections are major cause of infertility in dairy cows, with Escherichia coli being one of the most common pathogens. Its ability to colonise the endometrium, release endotoxins and form biofilms contributes to persistent infections and reduced treatment efficacy. This study aimed to isolate E. coli from postpartum cows with endometritis and evaluate their biofilm-forming ability. Uterine samples were collected from 70 crossbred cows between 28 and 35 days postpartum, yielding 83 bacterial isolates. Among these, 35 (42.16) were confirmed as E. coli based on cultural and biochemical characteristics. Biofilm formation was assessed using Congo Red Agar (CRA) and microtitre plate (MTP) assays. CRA assay detected biofilm production in 60 per cent of isolates, while MTP assay, identified 68.57 per cent as biofilm producers. Moderate biofilm formers were the most common phenotype across both assays. The presence of biofilm-forming E. coli highlights their role in the persistence of uterine infections and their resistance to host defenses and conventional antibiotics. These findings emphasize the importance of incorporating biofilm-targeted strategies in the management of postpartum endometritis to improve reproductive performance in dairy cows.