Phenotypic and Genotypic Characterization of Staphylococcus aureus of Mastitic Milk Origin from Cattle and Buffalo for some Virulence Properties

Mastitis is one of the most important diseases of dairy animals causing enormous financial loss and Staphylococcus aureus has been held the most common pathogen causing mastitis. The disease process is influenced by various virulence factors possessed by these organisms. In the present study 32 isolates from mastitic milk samples from cattle and buffalo were identified as S. aureus on the basis of their colony characteristics, biochemical tests and 23S rRNA ribotyping. All the isolates were subjected to different tests to detect production of virulence fators viz. coagulase, DNase, TNase and slime. In the present study production of coagulase, DNase, TNase and slime was shown by 100%, 93.7%, 100% and 96.87% isolates. The genotyping for capsular genes (cap5K and cap8K) revealed that 22 isolates (68.75%) were positive for cap5K and seven isolates (21.87%) were recorded positive for cap8K genes whereas three isolates (9.37%) were found nontypable for both cap5K and cap8K.