There have been a handful of recent reports about serious "flesh-eating" bacterial infections, including an August news story about a man from New Jersey who got the infection while fishing for crabs and may need to have all four of his limbs amputated. Other reports include a woman from Indiana who passed away after contracting flesh-eating bacteria while on vacation in Florida and a man in Texas who became infected and died after wade-fishing in the Gulf of Mexico.
So-called flesh-eating bacteria can spread quickly and cause necrotizing fasciitis (NF)—a serious infection that destroys the skin, underlying (subcutaneous) tissues and the tissues that cover muscles (fascia). This infection can be deadly, but it is also very rare. The Centers for Disease Control and Prevention (CDC) estimates that there are 700 to 1,200 cases of NF each year in the U.S. And while the CDC notes that these statistics are likely an underestimate, the number of NF infections does not appear to be on the rise.
NF typically does not spread from one person to another and most cases occur randomly. However, the people who are most at risk for contracting NF are those with an underlying condition that lowers the body's ability to fight infection, such as diabetes, kidney disease, liver disease, alcoholism, HIV, or cancer. Managing and/or treating these conditions can help lower the risk of contracting NF.
Bacteria that cause NF can enter the body through a break in the skin—this can be anything from an insect bite, minor cut, or injection site to a scratch, burn, bruise, or boil. Once the bacteria have penetrated under the skin, they release endotoxins (poisons associated with the bacteria's cell wall) and exotoxins (poisons released by the bacteria as waste products). These toxins restrict blood supply and kill the cells in the surrounding tissue.
The most common type of NF-causing bacteria is Group A Streptococci (Streptococcus pyogenes), which is the same bacterium that also causes "strep throat." Staphylococcus aureus, which is often linked to boils and food poisoning, is another type of bacteria that can cause NF. Examples of other bacteria known to cause NF include Bacteroides, Clostridium, Escherichia coli, Klebsiella, Aeromonas, and Vibrio vulnificus. Only particular strains of these bacteria have been associated with NF.
NF signs and symptoms typically appear within a few hours of infection. Early signs include redness, severe pain, and tenderness at the affected area as well as flu-like symptoms such as fever, sore throat, stomach ache, nausea, diarrhea, chills, and muscle aches. The redness spreads quickly and can become hot to the touch, shiny, and swollen. Pain may lessen at this point because the infected tissues and nerves are destroyed. If left untreated, the infection will spread to other areas of the body, leading to multiple organ failure, shock, and death.
Because NF spreads so rapidly, people with NF need to be diagnosed and treated as soon as possible. If NF is suspected based on a person's signs and symptoms, a healthcare practitioner may perform surgery and administer intravenous (IV) antibiotics without delay. Surgery, the "gold standard" for diagnosing NF, can detect foul-smelling discharge, lack of bleeding within the affected tissue, tissue death (necrosis), and loss of normal resistance of tissue, which are common in NF cases. During surgery, the healthcare practitioner can also determine how far the infection has spread and remove infected tissue (surgical debridement).
There are no specific laboratory tests that can diagnose NF, but there are a few tests available that can help monitor the disease and determine its severity, including a complete blood count (CBC) and basic metabolic panel (BMP). Results may show a high white blood cell (WBC) count, high blood urea nitrogen (BUN) and/or low blood sodium, but these may also be seen in other conditions. Cultures of fluid and/or tissue are often ordered to determine which bacteria are causing the infection and which antibiotics can be used to treat the infection. Computed tomography scans (CT scans) are accessible to many healthcare practitioners and can show signs of NF, such as accumulation of fluid or pus under the skin.
To minimize your chances of contracting NF, the CDC recommends good wound care:
- Clean all minor breaks to the skin with soap and water
- Clean and cover draining or open wounds with clean, dry bandages
- See a healthcare practitioner for puncture or deep wounds
- Wash hands often with soap and water or alcohol-based hand rub
The CDC also recommends avoiding hot tubs, swimming pools, lakes, rivers, and oceans if you have an open wound or skin infection.