False-colour transmission electron micrograph (TEM) of an individual bacterium of Staphylococcus aureus, a member of a genus of spherical, Gram- positive, non-motile bacteria. Many species cause disease in man through secretion of exotoxins: S. aureus is commonly present on skin & mucous membranes & causes boils & internal abscesses. S. pyogenes albus & S. pyogenes aureus are associated with suppurative (pus forming) infections. Other species produce toxins causing food poisoning. Magnification: X 26,000 at 35mm size.