Isolation and identification of Brucella abortus from aborted cattle and buffaloes and evaluation of their antibiogram

Samples (61) comprising 37 foetal stomach contents, 9 vaginal mucus and 15 foetal membranes from the cases of aborted cattle and buffaloes were processed for the isolation and identification of Brucella abortus. Seventeen (27.86%) isolates of B. abortus were isolated, 11 belonged to biotype 1, 3 belonged to biotype 3, and 3 belonged to biotype 2. Rose Bengal plate test (RBPT) conducted on sera of 51 animals detected 10 positive cases whereas with serum agglutination test (SAT) 11 positive cases were detected. Thus isolation was more sensitive as compared to RBPT and SAT. Maximum number of B. abortus (25.92%) isolations in cattle and in buffaloes (41.17%) were obtained from animals in the age group of 4-6 years. Maximum number of B. abortus isolations in cattle (30%) and in buffaloes (50%) were obtained from animals that aborted in 6-8 months of gestation. Brucellosis was maximum in indigenous cattle (50%) and in Murrah buffaloes (62.5%). Antibiotic sensitivity of B. abortus revealed that it was 94.11% sensitive to ampicillin, enrofloxacin and cotrimoxazole, 88.23% to gentamicin, streptomycin and chloramphenicol, 82.35% to neomycin, 76.47% to norfloxacin, 70.58% to amoxycillin, 17.64% to tetracycline and cephalexin and resistant to penicillin.