author(s)
S Choudhary, Diwakar, T Bhati and AK Kataria

abstract
The present study was undertaken to determine virulence associated protein-A (spa gene) in 30 S. aureus isolated from cattle with clinical mastitis. All the isolates were characterized by polymerase chain reaction to determine the frequency of spa (spa-X) gene wherein 93.33% isolates produced spa (x-region) gene amplicon. Of the 30 isolates, 19 isolates produced single amplicon and 9 isolates produced double amplicons. The size of amplicons obtained were 80, 200, 220, 250, 280, 300 and 320bp with a calculated number of 3, 4, 7, 3, 6, 13 and 1 repeats, respectively. The amplicon of 300bp was detected in 13 isolates followed by 220bp amplicon in seven, 280bp amplicon in six, 200bp amplicon in four, 250bp amplicon in three, 80bp amplicon in 3 and 320bp amplicon in one isolate.