The present study was conducted to test the prevalence of bovine mastitis caused by coliforms and to understand its antibiogram. A total of 173 milk samples were collected under sterile precautions from 168 cows presented to University Veterinary hospitals, Mannuthy and Kokkalai, University Livestock Farm, Mannuthy and other veterinary dispensaries in Thrissur district during the period from October 2017 to May 2018. Primary isolation on Brain heart infusion agar and blood agar yielded 123 bacterial isolates. Out of that, 90 were Gram positive organisms (73.17 per cent) and 33 were Gram negative organisms (26.82 per cent). Based on the cultural characteristics on Mac conkeys agar and Eosin methylene blue agar and biochemical characterization yielded 26 coliform organisms (21.13 per cent) which includes 14 Escherichia coli (11.38 per cent), 10 Klebsiella spp. (8.9 per cent), 1 Enterobacter spp. (0.81 per cent) and 1 Citrobacter spp. (0.81 per cent). All the isolates were subjected to in vitro antibiotic sensitivity studies using disc diffusion technique as per standard protocol. Antibiogram revealed that most coliforms were sensitive to ceftizoxime (53.84 per cent) followed by amoxicillin sulbactum (42.30 per cent), ceftriaxone tazobactum (34.61 per cent), cefoperazone sulbactum (26.92 per cent), ceftriaxone (15.38 per cent), tetracycline (15.38 per cent) and were resistant to chloramphenicol, gentamicin, co-trimoxazole and enrofloxacin. The present study revealed that prevalence of coliforms was comparatively lower than Gram positive organisms causing mastitis and ceftizoxime was found to be the most sensitive antibiotic against coliforms isolated from bovine mastitis.
Key words: Bovine, mastitis, prevalence, coliforms, antibiogram