Staphylococcus is a genus of gram-positive bacteria. The name comes from the Greek: σταφυλή (staphylē) which means "bunch of grapes" and κόκκος (kókkos) which means "granule". Under a microscope they appear round, because they are cocci. They form in grape-like clusters.
|This colorized scanning electron micrograph (SEM) shows clumps of methicillin-resistant Staphylococcus aureus|
The Staphylococcus genus includes at least forty species. Of these, nine have two subspecies and one has three subspecies. Most are harmless and live normally on the skin and mucous membranes of humans and other organisms. Found worldwide, they are a small component of soil microbial flora.