 Staphylococcus aureus is a gram-positive bacterium that causes various diseases including food poisoning and toxic shock syndrome through exotoxins such as SEA and SEB, which are super antigens that bind to class 2 MHC molecules on antigen-presenting cells and stimulate T cells. These proteins are highly resistant to denaturation and can trigger disease outbreaks in contaminated food. Multi-drug-resistant strains of S aureus are a concern in the clinical setting as they cause antibiotic-associated diarrhea in hospitalized patients. This article was authored by Victor E. Reyes, Ellen J. Beswick and Irina V. Pinchuk.