aureus is the predominant pathogen identified in skin infection due to its greater proclivity, compared with streptococci, to form abscesses, which also increases the probability of obtaining a positive culture. In patients with compromised immune systems, other, less-virulent β-hemolytic streptococci (eg, Streptococcus agalactiae in patients with diabetes mellitus), and even gram-negative pathogens, may cause skin and skin structure infections.
In an immunocompetent host, the vast majority of these infections are due to Staphylococcus aureus and β-hemolytic streptococci, primarily Streptococcus pyogenes. Skin and skin structure infections vary in severity and depth, from mild infections that can be treated with topical antibiotics to life-threatening necrotizing fasciitis requiring surgical intervention. Skin and skin structure infections are among the most common infectious diseases, with an estimated incidence of almost 500 cases per 10 000 person-years.
