What Is a Flesh Eating Bacterial Infection?

Read our main article on necrotizing fasciitis, also known as flesh-eating bacteria and flesh-eating disease »

Media reports have popularized the term flesh-eating bacteria to refer to a type of very rare but serious bacterial infection known as necrotizing fasciitis. Necrotizing fasciitis is an infection that starts in the tissues just below the skin and spreads along the flat layers of tissue (fascia) that separate different layers of soft tissue, such as muscle and fat. This dangerous and potentially deadly infection most commonly occurs in the arms, legs, and abdominal wall and is fatal in 30%-40% of cases.

Although necrotizing fasciitis may be caused by an infection with one or more than one bacterium, in most cases, the term flesh-eating bacteria has been applied to describe infections caused by the bacterium known as Streptococcus pyogenes. The term flesh-eating has been used because the bacterial infection produces toxins that destroy tissues such as muscles, skin, and fat. Streptococcus pyogenes is a member of the group A streptococci, a group of bacteria that are commonly responsible for mild sore throat (pharyngitis) and skin infections. Rarely, this form of strep bacterium causes severe illnesses such as toxic shock syndrome and necrotizing fasciitis. Most infections with group A streptococci result in mild illness and may not even produce symptoms.

Sometimes, other bacteria, including Klebsiella, Clostridium, E. coli, Staphylococcus aureus, or even a combination of different bacteria may produce necrotizing fasciitis. In 2012, a case was reported of a young woman who suffered a zip-lining accident on a river in West Georgia. She contracted an infection with the bacteria Aeromonas hydrophila, which produced a necrotizing infection that resulted in the loss of a leg and part of her abdomen. Vibrio vulnificus is a type of bacteria found in brackish water that has caused necrotizing fasciitis in swimmers who have been in infected water with open wounds.

The early stage of necrotizing fasciitis is characterized by symptoms of redness, swelling, and pain in the affected area. Blisters may be seen in the involved area of skin. Fever, nausea, vomiting, and other flu-like symptoms are common. Another characteristic of necrotizing fasciitis is that the symptoms develop very rapidly, usually within 24 hours after a wound in the skin has allowed the bacteria to invade the tissues beneath the skin. The pain is described as being more severe than would be expected from the appearance of the wound. Late symptoms can include death (gangrene) of affected areas with scaling, discoloration, or peeling of the skin. Amputation of affected extremities is sometimes necessary.

Many of the people who have developed necrotizing fasciitis have been in good health before developing the condition. People with chronic medical conditions (for example diabetes and cancer) or who have weakened immune systems are at an increased risk of developing necrotizing fasciitis. Recent wounds (including surgical incisions) and recent viral infections that cause a rash (such as chickenpox) may constitute an increased risk. Nevertheless, healthy people with strong immune systems have a very low risk of developing necrotizing fasciitis if they practice proper hygiene and wound care. Necrotizing fasciitis is not highly contagious and is only rarely spread from person to person. Usually, infection occurs by the bacteria entering the body through open areas on the skin.

Necrotizing fasciitis is treated with antibiotics, and early treatment is critical. Hospitalization, usually with treatment in the intensive-care unit (ICU), is required. Surgery to remove infected fluids and tissue is almost always necessary, along with medications to treat shock and other potential complications.

Good hygiene practices are the best way to prevent a bacterial infection of the skin. Prevention of infection includes avoidance of swimming in pools or open water sources, or soaking in hot tubs, with open wounds or sores. Additionally, keeping open wounds covered with dry bandages until healed, washing hands often, and proper care of wounds and injuries, including scrapes, blisters, and cuts, can prevent necrotizing fasciitis.

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