Staphylococcus aureus

Staphylococcus aureus is a Gram-positive opportunistic pathogen most commonly associated with skin and soft-tissue infections (SSTIs). This pathogen can also cause a diverse array of other important clinical manifestations. S. aureus primarily colonizes the anterior nares of the nose and secondarily colonizes the skin, oropharynx, vaginal wall, and intestinal tract. Colonization is a known risk factor of infection. S. aureus infections develop when the pathogen breaches the outer protective layers of the skin and mucosa. After invasion, it can survive innate defenses with expression of virulence factors. A complex network of global regulators tightly controls virulence gene expression, responding to host and environmental cues to coordinate expression. The S. aureus virulence repertoire contains matrix-binding adhesins for initial attachment, exo-enzymes for degrading host components, toxins and superantigens for subverting immune responses, surface-associated polysaccharide and capsule for protection, and a suite of other factors for surviving in the host and persisting in a biofilm state. Extensive genome sequencing has improved our understanding of disease-specific virulence factors and strain-level diversity across the species.