|Scanning electron microscopy micrograph of S. aureus colonies; note the grape-like clustering common to Staphylococcus species.|
Staphylococcus (from the Greek: σταφυλή, staphylē, "bunch of grapes" and κόκκος, kókkos, "granule") is a genus of Gram-positive bacteria. Under the microscope they appear round, because they are cocci, and form in grape-like clusters.
The Staphylococcus genus includes at least forty species. Of these, nine have two subspecies and one has three subspecies. Most are harmless and reside normally on the skin and mucous membranes of humans and other organisms. Found worldwide, they are a small component of soil microbial flora.