Coagulase gene based molecular detection of Staphylococcus aureus directly from mastitic milk samples of Murrah buffalo.

Abstract

The study was conducted to detect Staphylococcus aureus directly in mastitic milk of Murrah buffaloes using coagulase gene based specific polymerase chain reaction assay. Out of 628 samples, a total of 140 samples were found positive with four amplified products of size 960 bp, 870 bp, 740 bp and 610 bp in 8.57 percent, 19.28 percent, 29.29 percent and 42.85 percent of the milk samples, respectively. On PCR examination of Staphylococcus aureus found positive by bacteriological examination and biochemical tests, similar amplified products were observed in 9.37 percent, 21.09 percent, 32.03 percent and 37.5 percent of culture isolates (n=128) respectively. Ubiquitous PCR assay with amplified product of size 108 bp was used as an internal control for detection of Staphylococcus aureus. By this assay, nonviable Staphylococcus aureus could also be detected in milk samples of animals treated with antibiotics The study revealed that several coagulase gene types are responsible for genetic heterogeneity among Staphylococcus aureus isolated from mastitis cases in buffaloes and predominance of these amplified products shows significant variation over time paving way for understanding of epidemiology of mastitis in a particular location.