Vol. 12, Issue 3 (2023)

Author(s):
Komal Singh, Satish Yadav, Krishan Kumar Mishra, Neeraj Shrivastava, Rajeev Ranjan, Arpita Shrivastav, Amit Kumar Jha and Swatantra Kumar Singh

Abstract:
Staphylococcus aureus is a common causative agent of bovine subclinical mastitis and it has worldwide public health significance. Here, we aimed to determine the incidence of virulence factors of Staphylococcus aureus isolated from milk of subclinical bovine mastitis. Milk samples were collected from 402 lactating animals (242 dairy cattle and 160 buffaloes) from different farms located in Rewa district of Madhya Pradesh (India). The collected samples were investigated for subclinical mastitis using indirect screening tests. A total of 96 milk sample from 76 cattle and 20 buffaloes were positive for subclinical mastitis. The total incidence of Staphylococcus aureus was 28.13% with 28.95% in cattle and 25.00% in buffaloes. A total of 27 Staphylococcus aureus isolates obtained from bovine subclinical mastitis and positive to catalase, were analyzed for production virulence factors. Out of 27 isolates, all the Staphylococcus aureus isolates (100%) were found positive for mannitol fermentation, coagulase production, clumping factor test, gram staining, novobiocin susceptibility and polymyxin-B resistance. Out of 27 isolates, the Voges-proskauer test, alpha, beta and alpha-beta haemolysin production were observed in 85.19%, 29.62%, 55.55% and 14.81% isolates respectively. Further the isolates were subjected to evaluation of virulence determinant spa genes. Virulence genes of Staphylococcus aureus strains isolated from bovine milk and spa genes were found in 100.0% isolates indicating the emergence, spread and pathogenicity of Staphylococcus aureus. Thus, the high incidence of Staphylococcus aureus mastitis is an important concern for diary industry of Madhya Pradesh (India), since the strains of this pathogen are with number of virulence factors and this is a concern for both animal and public health.