Isolation, Identification and Antibiogram Study of E. coli Isolated from Bovine Mastitis Milk from Various Dairy Farms of Jabalpur, Madhya Pradesh, India

Bovine mastitis is the most common disease in dairy animals. It is the inflammation of the udder, usually caused by various bacterial pathogens, continues to pose a significant challenge to animal health and productivity. Mastitis is considered a serious problem of dairy animals, affecting animal welfare as well as economically leading to huge losses to the dairy industry. The present study was conducted to isolate, identify and to determine the antimicrobial resistance profile of E. coli from bovine mastitis milk in and around Jabalpur. A total of 210 bovines were screened for mastitis through the California Mastitis Test (CMT), and positive samples were inoculated in Brain Heart Infusion broth, followed by Nutrient Agar and MacConkey lactose Agar. These samples were further inoculated onto specific culture media for isolation of E. coli and further identified by Gram’s staining, biochemical tests/ BD Phoenix M50 automated machine. The antimicrobial sensitivity of isolates was tested by the Kirby-Bauer disc diffusion method. A total of 34/210 (16.19%) samples were reported positive for clinical mastitis. Out of these six isolates (17.64%) E. coli was confirmed. They were showing pink colonies on MLA and green metallic sheen on EMB Agar. On Gram’s staining, they appear as short rods. Genotypic identification using 16S rRNA revealed that 100% phenotypically confirmed isolates of E. coli were found to be positive. The antibiogram revealed that the isolates of E. coli showed resistance against Ampicillin (83.33%) and Cefoxitin (66.66%), while showing sensitivity towards Amikacin (83.33%), Gentamicin (83.33%) and Tetracycline (83.33%). These results highlight the significant concern of antimicrobial resistance in E. coli isolates from mastitic milk and emphasize the critical need for prudent antimicrobial use and ongoing surveillance to effectively manage mastitis and mitigate the impact of resistance in dairy farming.