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.
- The production of several different toxins
- Enterotoxins A, D, F (TSST1)
- Exfoliative toxin ( causing scalded skin syndrome
- Cytolytic toxins (causing cell & tissue damage).
- Production of enzymes
- Catalase – distinguishes staphylococci from streptococci
- Coagulase – distinguishes S. aureus from other staphylococci
- Hyaluronidase & lipase – aid in skin colonization/infection spread
- Beta-lactamase – breaks down the beta-lactam antibiotics, e.g., penicillins, cephalosporins, carbapenems and monobactams.