Staphylococcus aureus infection is responsible for subclinical bovine mastitis, which has greatly impacted the diary industries. The infection could lead to economic burdens due to the decrease in milk production and increases in therapeutic costs. This research study investigated the role of alternative sigma factor B (σB), which has been shown to be a global regulator for S. aureus infections, in a mastitis-causing S. aureus strain, RF122. We discovered that σB is essential for biofilm formation and involved in response to H₂O₂ stress. Nevertheless, our results showed that σB plays a minor role in resistance to antiseptics (e.g., povidone-iodine and chlorhexidine) and antibiotics often used in dairy farm. In addition, RNA sequencing identified 225 σB-dependent genes, which involved in stress response, pathogenesis, and metabolic mechanisms. This study help understanding of S. aureus persistence mechanisms in bovine mastitis and suggest the potential of σB as drug target.

Reference:  Front. Microbiol., 2019, 2493