Staphylococcus aureus

Staphylococcus aureus is a Gram-positive, round-shaped bacterium that is a member of the Firmicutes, and it is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although S. aureus usually acts as a commensal of the human microbiota it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning.

Staphylococcus aureus (S. aureus), a Gram-positive and round-shaped bacterium, is a member of the firmicutes and a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive to catalase and nitrate reduction and is a facultative anaerobe that can grow without oxygen. Although S. aureus usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen that is a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. S. aureus infections can spread through contact with pus from an infected wound, skin-to-skin contact with an infected person, and contact with objects used by an infected person such as towels, sheets, clothes, or athletic equipment. The treatment of choice for S. aureus infection is penicillin. As an antibiotic derived from some penicillium fungal species, penicillin inhibits the formation of peptidoglycan cross-linkages that provide the rigidity and strength in a bacterial cell wall.