Phenotypic and genotypic determination of biofilm forming Staphylococcus aureus causing bovine mastitis

Mastitis is causing huge economic losses to the dairy industry. Among different mastitis causing pathogens, Staphylococcus aureus is the leading bacterial cause involved in mastitis with more than 30 virulence factors. Biofilm production is one of the important virulence factor leading to treatment failure. Therefore, the present study was planned to investigate the percent prevalence of biofilm producing Staphylococcus aureus on the basis of genotypic and phenotypic basis. A total of 102 Staphylococcus aureus isolated from mastitic milk samples were cultured on congored agar with 5% glucose for phenotypic expression of biofilm and for molecular detection PCR assay targeting icaA and icaD gene was employed. Characteristic black and brown colnies typical of congored agar were seen in 88.23% isolates. Positive amplicon of 1315 bp and 381 bp was generated in 91.17% and 92.15% isolates corresponding to amplification of icaA and icaD gene, respectively.