Staphylococcus Aureus - Microbiology

Microbiology

S. aureus ( /ˌstæfɨlɵˈkɒkəs ˈɔriəs/, Greek σταφυλόκοκκος, "grape-cluster berry", Latin aureus, "golden") is a facultative anaerobic Gram-positive coccal bacterium, also known as "golden staph" and Oro staphira.
In medical literature the bacteria is often referred to as S. aureus or Staph aureus. Staphylococcus should not be confused with the similarly named and medically relevant genus Streptococcus. S. aureus appears as grape-like clusters when viewed through a microscope, and has large, round, golden-yellow colonies, often with hemolysis, when grown on blood agar plates. S. aureus reproduces asexually by binary fission. The two daughter cells do not fully separate and remain attached to one another. This is why the cells are observed in clusters.

S. aureus is catalase-positive (meaning it can produce the enzyme catalase), so is able to convert hydrogen peroxide (H₂O₂) to water and oxygen. This test is sometimes used distinguish staphylococci from enterococci and streptococci. Previously S. aureus was differentiated from other staphylococci by the coagulase test. However it is now known that not all S. aureus are coagulase positive and that incorrect species identification can impact effective treatment and control measures.

Further information: Coagulase-positive staphylococcal infection