Encyclopedia of Ayurvedic Medicinal Plants

Domain:            Bacteria

Kingdom:         Bacteria

Phylum:           Firmicutes

Class:   Cocci

Order:  Bacillales

Family: Staphylococcaceae

Genus:  Staphylococcus

Species:            S. aureus

Binomial name

Staphylococcus aureu

                      S. aureus is a Gram-positive coccus, which appears as grape-like clusters when viewed through a microscope and has large, round, golden-yellow colonies, often with β-hemolysis, when grown on blood agar plates. The golden appearance is the etymological root of the bacteria's name: aureus means "golden" in Latin.

                     S. aureus is catalase positive and thus able to convert hydrogen peroxide (H2O2) to water and oxygen, which makes the catalase test useful to distinguish staphylococci from enterococci and streptococci. A large percentage of S. aureus can be differentiated from most other staphylococci by the coagulase test: S. aureus is primarily coagulase-positive, while most other Staphylococcus species are coagulase-negative. However, while the majority of S. aureus are coagulase-positive, some may be atypical in that they do not produce coagulase. Incorrect identification of an isolate can impact implementation of effective treatment and/or control measures. It is medically important to identify S.aureus correctly as S.aureus is much more aggressive and likely to be antibiotic-resistant. Coagulase-negative S. aureus appears to be an increasing problem that clinical laboratories should be aware of. They are as virulent as those producing coagulase and can colonize, cause infections and spread among patients.

               S. aureus has about 2,600 genes and 2.8 million bp of DNA in its chromosome. Plasmids can also comprise part of the species' genome.

                  The species has been subdivided into two subspecies: S. aureus aureus and S. aureus anaerobius. The latter requires anaerobic conditions for growth, is an infrequent cause of infection, and is rarely encountered in the clinical laboratory.