Detection of Some Important Bacterial Agents Causing Bovine Mastitis

The present work was conducted to isolate and detect by PCR three important bacterial pathogens (Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus uberis) associated with bovine mastitis. A total of 36 clinical mastitic milk samples were collected from various cross bred cattle presented in the Veterinary Clinical complex centre, Bikaner, Rajasthan. Out of 36 milk samples processed, we recovered 51 isolates belonging to Staphylococcus aureus (18), Streptococcus uberis (5), Streptococcus agalactiae (2), Staphylococcus intermedius (8), Staphylococcus chromogens (4), Bacillus sp. (2) and Escherichia coli (12). The PCR conducted directly on milk samples with species-specific primers of Staphylococcus aureus, Streptococcus agalactiae and Streptococcus uberis revealed 19, 7 and 2 samples respectively positive for these pathogens. The study showed highest incidence of Staphylococcus aureus (50.0%) followed by Streptococcus uberis, (13.89%) and Streptococcus agalactiae (5.5%) by culture-based method while incidence rate recorded by PCR of Staphylococcus aureus (52.77%) followed by Streptococcus uberis, (19.44%) and Streptococcus agalactiae (5.5%) associated with bovine mastitis. Thus, PCR was found to have a good correlation with cultural method for diagnosis of the causative agent of mastitis in a short span of time