Bacteria of the genus Staphylococcus are gram-positive cocci that occur individually, in pairs, and in irregular grapelike clusters. The term Staphylococcus is derived from the Greek term staphyle, which means a bunch of grapes. Staphylococci are nonmotile, non–spore-forming, and catalase-positive bacteria. The cell wall contains peptidoglycan and teichoic acid. The organisms are resistant to temperatures as high as 50°C, to high salt concentrations, and to drying. Colonies are usually large (6-8 mm in diameter), smooth, and translucent. The colonies of most strains are pigmented, ranging from cream-yellow to orange.