Identification of Toxic Shock Syndrome Toxin-1 (TSST-1) gene in Staphylococcus aureus isolated from bovine mastitis milk

Staphylococcus aureus is a major causative pathogen of clinical and subclinical mastitis of dairy domestic ruminants. This agent produces a variety of extracellular toxins and virulence factors including Toxic Shock Syndrome Toxin-1 (TSST-1) which is the major cause of Toxic Shock Syndrome (TSS). In this study 58 S. aureus isolates obtained from 9 dairy herds in East and West Azerbaijan provinces of Iran. The tested isolates were identified on the basis of the cultural and biochemical properties as well as by amplification of the aroA gene, specific to S. aureus. Isolates were also analyzed for the presence of the TSST-1 encoding gene (tst) using Polymerase Chain Reaction (PCR). tst gene 350 bp was detected in 9 (15.5%) of the total number of 58 isolates. The present study revealed that the PCR amplification of the aroA gene could be used as a powerful tool for identification of S. aureus from the cases of bovine mastitis. Results also showed that the strain of S. aureus which caused mastitis can potentially produce staphylococcal toxic shock syndrome toxin-1. Overall, our results suggest that it is of special importance to follow the presence of TSST-1 producing S. aureus in foodstuffs, especially for protecting the consumers from toxic shock syndrome.