Skin bacteriology and the role of Staphylococcus aureus in infection

Many of the staphylococci and coryneforms that inhabit normal human skin do not cause skin disease. Amongst the remainder the mechanisms of pathogenicity vary widely. For Proteus, Pseudomonas and Brevibacterium species proteolysis is a major determinant. The precise role of Corynebacterium minutissimum in erythrasma and the propionibacteria in acne is not known. Staphylococcus aureus, however, produces a wide range of non-specific agents, such as haemolysins and leucocidins as well as highly specific toxins such as the epidermolytic toxins involved in bullous impetigo and scalded skin syndrome. Most of the current attention, however, is devoted to the role of the enterotoxins and toxic shock toxin as superantigens, with emphasis on their role in atopic dermatitis. Molecularly similar toxins in the streptococci play a similar role and may also have a role in the aetiology of psoriasis.