Necrotizing Fasciitis

In necrotizing fasciitis group A beta-hemolytic Streptococcus and Staphylococcus aureus, alone or together, are most often the primary infecting bacteria. There are more than 80 types of the causative bacteria. S. pyogenes, making the epidemiology of GAS infections complex. Other aerobic and anaerobic pathogens include Bacteroides, Clostridium, Peptostreptococcus, Enterobacteriaceae, coliforms, Proteus, Pseudomonas, and Klebsiella.

Risk factors for contracting necrotizing fasciitis include advanced age, human immunodeficiency virus infection, alcohol abuse, and varicella infection. Patients with chronic illness, such as cancer, diabetes, cardiac and pulmonary disease, and kidney disease requiring hemodialysis, are also at risk for contracting necrotizing fasciitis. Those using steroids are more susceptible to GAS infection due to debilitated immune responsiveness.

The infecting bacteria in this disorder enter the host through a local tissue injury or a breach in a mucous membrane barrier. Wounds as minor as pinpricks, needle punctures, blisters, and abrasions or as serious as a traumatic injury or surgical incision can provide an opportunity for bacteria to enter the body.

The organisms proliferate in an environment of tissue hypoxia caused by trauma. recent surgery or a medical condition that compromises the patient. The end product of the invasion is necrosis of the surrounding tissue, which accelerates the disease process by creating a favorable environment for these organisms.

Signs and Symptoms
There are 2 important symptoms to watch out for: