Flesh-eating bacteria” is a term mentioned in the media every now and then, usually in a very sensational way. Often, the media reports are related to a case of a person who got a limb amputated after a severe infection. Many of the reported cases are in persons who went to the beach in Florida.
“Flesh-eating bacteria” is a loose term given to the medical condition called necrotizing fasciitis (pronounced fashi-itis). Necrotizing fasciitis is an infection of the deeper layer of tissue below the skin (this layer of tissue is called fascia). Bacteria is introduced into this deep layer after something as simple as a scratch on the skin, or from infection of an ingrown hair, for example. Often, however, there is no obvious entry point for the bacteria. Once the bacteria gets to the deep layer, it multiplies rapidly. The resulting inflammation caused by the infection, plus toxins released from the bacteria, lead to damage and eventual death of the tissues. The infection spreads rapidly across the tissue (fascial) plains, resulting in extensive amounts of dead tissue. The process of tissue death is referred to as necrosis, hence the name of the condition – necrotizing (from necrosis) fasciitis (from fascia).
As mentioned in the title, the germ(s) causing necrotizing fasciitis is not named “flesh-eating bacteria.” There are numerous types of bacteria that can cause necrotizing fasciitis, but commonly, group A Streptococcus, Staphylococcus aureus, Clostridium species, and Vibrio vulnificus are culprits. Often, it is a combination of several types of bacteria that is causing the infection. Common locations of infection include the limbs and the genital region. A characteristic of necrotizing fasciitis is severe pain out of keeping with the appearance of the affected area. Initially the overlying skin looks normal. However, very rapidly, within a matter of hours, discoloration of the skin and blistering occurs. The patient often develops fever and malaise. Classically, patients will say “it all happened so fast!”
Necrotizing fasciitis is a surgical emergency. Treatment hinges on surgery to to remove all the dead tissue. Often, the patient will require multiple surgeries before all the infection is cleaned up. Unfortunately, sometimes the extent to tissue death is so great, that a limb has to be amputated. Antibiotics are an important aspect of treatment, obviously.
When I was in medical school, necrotizing fasciitis was described as a rare condition. However, I would say that I get a case almost every month. This may be because I work in an area where the prevalence of diabetes is extremely high. Most of my cases I get are diabetic and many of them involve the genital area although I have had cases involving legs and a couple involving the forearm.
Generally speaking, necrotizing fasciitis is more common nowadays because of an increase in the number of people with conditions which affect the immune system’s ability to adequately fight infection. Some of these conditions include diabetes as mentioned above, cancer, HIV infection, alcoholism, and poor circulation.
Prevention, as with many infections diseases, involves diligently managing any underlying medical problems, particularly those which may weaken the immune system. If severe pain of any part of the body develops, especially if it is associated with fever and malaise, medical attention should be sought immediately. If during a visit to the beach you are cut by a piece of coral or stuck with the fin of a fish, medical attention may be needed, should there be worsening redness and pain of the area. Regarding sea-bathing, most people are not going to have any problems after a visit to the beach. I grew up in the Caribbean and going to the beach was a regular affair. If simple sea-bathing was strong risk factor for developing necrotizing fasciitis, then the Caribbean would be decimated!