Necrotizing fasciitis

What is necrotizing fasciitis?
Necrotizing fasciitis is defined pathologically by necrosis of the deep soft tissue, including fascia, with relative sparing of skeletal muscle. It results in extensive necrosis that often largely spares the overlying skin. It is most often caused by group A streptococcus.

What other organisms besides group A streptococcus can cause necrotizing fasciitis?
The most common presentations of necrotizing fasciitis involve the abdominal wall or perineum, often with polymicrobial infection due to spontaneous, traumatic, or surgical disruption of bowel integrity, particularly in a patients with diabetes or immunosuppression. In a patient who is healthy and has not recently undergone surgery, a monomicrobial infection is the rule with group A streptococcus or Staphylococcus aureus, including methicillin-resistant S. aureus, implicated most frequently. Necrotizing fasciitis arising as a complication of infection in the setting of drug abuse is often caused by clostridium species, notably Clostridium sordellii in association with black-tar heroin.

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New England Journal of Medicine - Vol. 360, No. 3, January 15, 2009