Staphylococcus aureus beta toxin is a toxin produced by Staphylococcus aureus. It is a form of sphingomyelinase called sphingomyelinase C. This enzyme is toxic to a variety of cells, including erythrocytes, fibroblasts, leukocytes, and macrophages. Susceptible cells are subject to lysis of exposed sphingomyelin on their membrane surfaces.
The beta toxin exhibits maximum activity at 10 ðC, at 37 ðC (normal body temperature) seems to be inactive.