6 Qahtani, 2006; Akpakaet al., 2006). Presumptive Staphylococcus

6 Classification of Staphylococci:

Staphylococcal species
have traditionally being differentiated using different phenotypic testssuch as
the coagulase and the DNase test (Martineau et
al., 2000; Mugaluet al., 2006;
Belloand Qahtani, 2006; Akpakaet al.,
2006). Presumptive Staphylococcus aureus
can beidentified based on DNase tests and growth on mannitol salt agar (MSA). Staphylococcus aureus gives a positive
coagulase and DNase test while most species of coagulase negative staphylococci
give a negative DNase test (Kateeteet al,
2010).

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1.1.7 Biochemical identification

Assignment
of a strain to the genus Staphylococcus requires it to be a Gram-positive
coccus that forms clusters, produces catalase, has an appropriate cell wall
structure (including peptidoglycan type and teichoic acid presence) and G + C
content of DNA in a range of 30–40 mol%Staphylococcus species can be
differentiated from other aerobic and facultative anaerobic, Gram-positive
cocci by several simple tests. Staphylococcus species are facultative anaerobes
(capable of growth both aerobically and anaerobically). All species grow in the
presence of bile salts.All species were once thought to be coagulase-positive,
but this has since been disproven.( Ryan KJ, Ray CG, eds. 2004, PreTest,
Surgery, 12th ed, Matthews KR 1997).

Growth
can also occur in a 6.5% NaCl solution. On Baird Parker medium, Staphylococcus
species grow fermentatively, except for S. saprophyticus, which grows
oxidatively. Staphylococcus species are resistant to bacitracin (0.04 U disc:
resistance =