Staphylococcal Skin Infections

Staphylococcus aureus, a Gram-positive bacterium, is part of the skin surface microbiota but can cause skin infection when the skin barrier is breached.

S. aureus uses surface adhesins such as clumping factor B and SasG to attach to host proteins loricrin and cytokeratin, present on skin cells.

This attachment allows the bacteria to persist locally and initiate bacterial infection.

As the infection progresses, coagulase, a S. aureus virulence factor, forms a protective fibrin clot, which helps localize the infection by shielding it from phagocytosis.

It also produces leukocidin, a toxin that destroys white blood cells.

S. aureus invasion causes localized skin infections, such as pimples or folliculitis. These appear as red, raised bumps filled with pus.

When the infection spreads deeper, it leads to the formation of a furuncle.

Carbuncles are clusters of furuncles that extend into the deeper dermis and subcutaneous tissue.

Staphylococcal scalded skin syndrome is characterized by blistering and peeling of the outer skin layer, caused by exfoliative toxins of S. aureus.