S. aureus is the most pathogenic member of the genus Staphylococcus; it possesses several factors that contribute to its virulence:
- Structural components of its cell wall function as a protective barrier, aid in adherence to mucous membranes, and allow the organism to resist phagocytosis.
- Production of several different toxins:
- Enterotoxins A, D, F (TSST-1)
- Exfoliative toxin (causing scalded skin syndrome)
- Cytolytic toxins (causing cell and tissue damage)
- Production of enzymes:
- Catalase – distinguishes staphylococci from streptococci
- Coagulase – distinguishes S. aureus from other staphylococci
- Hyaluronidase and lipase – aid in skin colonization/infection spread
- Beta-lactamase – breaks down the beta-lactam antibiotics (e.g., penicillins, cephalosporins, carbapenems, monobactams)
