Virulence gene profile and antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis in Kashmir, India

Abstract

The Staphylococcus aureusis often responsible for a number of diseases in humans and animals, and it is considered as a main etiological agent of bovine mastitis. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. This study investigated virulence genes, prevalence and antibiogram profile of S. aureus isolated from dairy cows suffering from mastitis in the Kashmir. A total of 70 S. aureus isolates were obtained from 250 mastitic milk samples collected from both organized (47/150) and unorganized (23/100) dairy farms. Five pathogenic factors including clfA, hld, seo, lukM, and coa and one resistance gene mecAgene were checked through PCR. Clumping factor gene (clfA) was found in most of the isolates with a percentage of 81.42 % whereas,hld, seo, lukM, and coa were present in 61.2, 54.28, 70, and 71 percent of isolates, respectively. However, amplification of coagene yielded DNA bands of two different sizes. A high percentage of antimicrobial resistance rates were observed, wherein, Ampicillin showed highest resistance with 85.7 %, followed by Kanamycin, Cefotaxime, Sulphadizine and Streptomicin showing 71.42 %, 54.28 %, 51.48 % and 42 %, respectively. A high frequency of Methicillin resistant S. aureus (MRSA 28.57 %) was observed in these isolates and all methicillin resistant isolates were found to be positive for mecA gene via PCR amplification. These results revealed that mastitis-associated S. aureus among bovines of Kashmir is able to accumulate different virulence factors and resistance to antimicrobials, making the treatment of infections difficult.