: any of a genus (Staphylococcus) of nonmotile gram-positive spherical bacteria that occur singly, in pairs or tetrads, or in irregular clusters and include causative agents of various diseases (as skin infections, food poisoning, and endocarditis)
New Latin, from Greek staphylē bunch of grapes + New Latin -coccus
First Known Use: 1887
Medical Definition of STAPHYLOCOCCUS
capitalized: a genus of nonmotile gram-positive spherical bacteria that is placed in either of two families (Staphylococcaceae or Micrococcaceae), contains forms occurring singly, in pairs or tetrads, or in irregular clusters, and includes causative agents of various diseases and disorders (as food poisoning, skin infections, and endocarditis)
Any of the spherical bacteria that make up the genus Staphylococcus. The best-known species are present in great numbers on the mucous membranes and skin of all humans and other warm-blooded animals. The cells characteristically group together in grapelike clusters. Staphylococci are gram-positive (seegram stain) and stationary and do not require oxygen. Of significance to humans is the species S. aureus, an important agent of wound infections, boils, and other human skin infections, and one of the most common causes of food poisoning. It also causes udder inflammation in domestic animals and breast infections in women. The largest cause of hospital infections (accounting for almost 15%), staph is often difficult to treat because of its increasing resistance to antibiotics.