Staphylococcus is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. Staphylococcus species are facultative anaerobic organisms (capable of growth both aerobically and anaerobically).
The name was coined in 1880 by Scottish surgeon and bacteriologist Alexander Ogston (1844–1929), following the pattern established five years earlier with the naming of Streptococcus. It combines the prefix "staphylo-" (from staphylē), and suffixed by the Modern (from kókkos).
Staphylococcus was one of the leading infections in hospitals and many strains of this bacterium have become antibiotic resistant. Despite strong attempts to get rid of them, staph bacteria stay present in hospitals, where they can infect people who are most at risk of infection.
Staphylococcus includes at least 43 species. Of these, nine have two subspecies, one has three subspecies, and one has four subspecies. Many species cannot cause disease and reside normally on the skin and mucous membranes of humans and other animals. Staphylococcus species have been found to be nectar-inhabiting microbes. They are also a small component of the soil microbiome.
The taxonomy is based on 16s rRNA sequences, and most of the staphylococcal species fall into 11 clusters:
S. aureus group – S. argenteus, S. aureus, S. schweitzeri, S. simiae
S. auricularis group – S. auricularis
S. carnosus group – S. carnosus, S. condimenti, S. debuckii, S. massiliensis, S. piscifermentans, S. simulans
S. epidermidis group – S. capitis, S. caprae, S. epidermidis, S. saccharolyticus
S. haemolyticus group – S. borealis, S. devriesei, S. haemolyticus, S. hominis
S. hyicus-intermedius group – S. agnetis, S. chromogenes, S. cornubiensis, S. felis, S. delphini, S. hyicus, S. intermedius, S. lutrae, S. microti, S. muscae, S. pseudintermedius, S. rostri, S. schleiferi
S. lugdunensis group – S. lugdunensis
S. saprophyticus group – S. arlettae, S. caeli, S. cohnii, S. equorum, S.