Taxonomy and typing

The revolution in staphylococcal taxonomy that followed the initial publications of W. E. Kloos and K-H. Schleifer (see below) has led to a much greater appreciation of the ecology of staphylococci on skin but has invalidated much earlier work. There are now 28 species and several subspecies of Staphylococcus (Table 6.1); subdivision within these species is possible on phenotypic or genotypic grounds and the chemistry underlying the taxonomy has been well explored. The principal habitat of staphylococci is the skin and some mucous membranes of mammals and birds, though few birds and virtually no non-mammalian animals have been studied.

Staphylococci are generally aerobic, Gram-positive cocci, which appear in irregular, so-called grape-like clusters under the microscope, although single and paired cells are the most common in fluid culture. They are catalase positive, have a mol per cent G + C of 30–37, possess teichoic acid in the cell wall and have glycine in the interpeptide bridge of peptidoglycan, lack cytochromes c and d, and have MK6–8 as the major menaquinones. This serves to separate the staphylococci from micrococci with which they were formerly linked, as Micrococcus spp. have a mol per cent G + C of 66–75, lack teichoic acid and glycine, possess cytochrome c and d, and have MK7(H2)–9(H2) as major quinones. Micrococcus and Staphylococcus are now regarded as very distinct genera.