title: Polymorphism in spa gene of Staphylococcus aureus from bovine subclinical mastitis.
abstract: OBJECTIVE
  The virulence-associated protein-A of Staphylococcus aureus, encoded by spa gene shows a variation in length in different strains. In this study, the spa gene variation in S. aureus strains was studied which were isolated from subclinical cases of bovine mastitis.
  
  
  METHODS
  About 38 isolatesof S. aureus were recovered from Holstein-Friesian (HF) crossbred (n=16) and Rathi cattle (n=22) with subclinical mastitis as per standard procedures, and these isolates were subjected to amplification of spa gene (X-region) by polymerase chain reaction and calculation of number of tandem repeats were done.
  
  
  RESULTS
  Of the 16 isolates from H-F crossbred cattle, all with the exception of one isolate produced spa amplicon. Seven isolates produced amplicons of 200 bp, one produced 160 bp, and other seven produced spa amplicon of 150 bp with calculated number of 6, 5, and 4 repeats, respectively, whereas nine different types of amplicons were produced by 22 S. aureus isolates from Rathi cattle, viz., 280, 250, 240, 200, 190, 180, 170, 150, and 140 bp with 10, 8, 8, 6, 6, 6, 5, 4, and 4 repeats, respectively. One of the isolates from Rathi cattle produced two spa amplicons (150 and 190 bp).
  
  
  CONCLUSIONS
  A greater polymorphism was observed in the S. aureus isolates from Rathi cattle than from H-F crossbreds with subclinical mastitis.
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Taruna
authors.initials: T
authors.lastname: Bhati
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Prerna
authors.initials: P
authors.lastname: Nathawat
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, Post Graduate Institute of Veterinary Education and Research, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Sandeep Kumar
authors.initials: SK
authors.lastname: Sharma
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Rahul
authors.initials: R
authors.lastname: Yadav
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Bishnoi
authors.affiliation: Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animals Sciences, Bikaner, Rajasthan, India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Kataria
keywords: Staphylococcus aureus; cattle; polymorphism; protein-A; spa gene; subclinical mastitis