Polymorphism in spa gene of Staphylococcus aureus from bovine subclinical mastitis.

Taruna Bhati,Rahul Yadav,Anil Kumar Kataria,Sandeep Kumar Sharma,Jyoti Bishnoi,Prerna Nathawat

doi:10.14202/vetworld.2016.421-424

Abstract

Aim: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.Materials and 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).Conclusion:A greater polymorphism was observed in the S. aureus isolates from Rathi cattle than from H-F crossbreds with subclinical mastitis.

Highlights

Bovine mastitis is a well-known challenge to dairy industry in India
Figure-1: Polymerase chain reaction amplicons of spa gene (X-region) of Staphylococcus aureus isolates from Holstein–Friesian crossbred cattle (C1-C9) with subclinical mastitis
Figure-2: Polymerase chain reaction amplicons of spa gene (X-region) of Staphylococcus aureus isolates from Holstein–Friesian crossbred cattle (C10-C16) and Rathi cattle (R1-R12) with subclinical mastitis

Summary

Introduction

Bovine mastitis is a well-known challenge to dairy industry in India. It affects the economy of farmers and of the country leading to an estimated annual loss of around US $526 million [1]. Among the various clinical forms of mastitis caused by S. aureus, subclinical cases have special importance as they go unnoticed and affect production performance of animal to a large extent [3]. The development and severity of mastitis depend on the production of virulent protein known as protein-A [4]. This protein is encoded by spa gene which has been shown to have a high degree of variability in size [5]. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

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