Skin and soft tissue infection: microbiology and epidemiology.

Skin and soft tissue infections (SSTIs) are common and range in severity from minor, self-limiting, superficial infections to life-threatening diseases requiring all the resources of modern medicine. The classification of SSTIs can be based on the anatomical site, clinical severity or microbial cause, but some classifications divide SSTIs into complicated and uncomplicated infections. Community-acquired SSTIs are most commonly caused by staphylococci or streptococci, but almost any organism is capable of causing inflammation within soft tissue. Recent epidemiological trends have shown an increase not only in healthcare-associated meticillin-resistant Staphylococcus aureus (MRSA), but also in MRSA acquired in the community. Many of the latter strains produce exotoxins and are epidemiologically distinct from healthcare-acquired strains. Factors that may affect the microbial cause include underlying disease such as diabetes or immune dysfunction; hospital attendance, injecting drug use, travel, animal contact and environmental contamination.