Staphylococcus /staf′ilōkok″əs/ pl. staphylococci [Gk, staphyle + kokkos, berry] , a genus of nonmotile spheric gram-positive bacteria. Some species are normally found on the skin and in the throat. Certain species cause severe purulent infections or produce an enterotoxin, which may cause nausea, vomiting, and diarrhea. Life-threatening staphylococcal infections may arise within hospitals. Staphylococcus aureus is a species frequently responsible for abscesses, endocarditis, impetigo, osteomyelitis, pneumonia, and septicemia. S. epidermidis, formerly called S. albus, occasionally causes endocarditis in the presence of intracardiac prostheses. See also staphylococcal infection. −staphylococcal, adj.