The following statement(s) is/are true concerning necrotizing fascitis

a. Mortality rates as high as 40% can be expected

c. An impaired immune system is a common factor predisposing to this condition

d. The infection is usually polymicrobial

e. Necrotizing fascitis is most likely to develop in the face of impaired fascial blood supply

Necrotizing fascitis is an uncommon infection of the deep and superficial fascia that is associated with mortality as high as 40% in many series. Although many underlying disease processes predispose patients to necrotizing fascitis, three common factors are almost invariably present: 1) impairment of the immune system; 2) compromise of fascial blood supply, and 3) the presence of microorganisms that are able to proliferate within this environment. Infections of this type are usually polymicrobial in nature, with gram-positive organisms such as staphylococci and streptococci, gram-negative enteric bacteria, and gram-negative anaerobic being frequently identified. These polymicrobial cultural results are assuredly indicative of the occurrence of a synergistic process, perhaps in large part accounting for the severity of these infections. Some microorganisms possess virulence factors that, in conjunction with an underlying host predisposition, allow this disease process to occur without dependence on other bacteria. Examples of such bacteria include Clostridium, Pseudomonas, and Aeromonas. In these patients, the process is often fulminant and is frequently associated with cellulitis, myositis, fascitis, and bacteremia with attendant high mortality.