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Flesh-eating bacteria and the beach

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Every summer we hear terrifying reports about people who went for a swim, only to find themselves fighting for life and limb in the hospital a few days later. These people are the unfortunate victims of necrotizing fasciitis, a rapidly-progressing infection caused by certain bacteria. These bacteria interfere with blood circulation, which leads to the death (necrosis) and gruesome decay of tissue, which is why it is commonly called “flesh-eating.”

The most frequent culprit of necrotizing fasciitis is Group A Streptococcus (group A strep), but these bacteria are not associated with swimmers. If contracted from water, the culprits could be Aeromonas (fresh water) or Vibrio vulnificus (ocean or brackish water). V. vulnificus thrives in water that is 70 degrees Fahrenheit or warmer, which is why numerous cases have been reported in areas contacting the Gulf of Mexico.

All flesh-eating bacteria require a port of entry to get under one’s skin. Any open cut or abrasion, including a fresh tattoo or insect bite, can be sufficient for the pathogen to enter the body. Once it breaches the skin and gets into the bloodstream, the bacteria multiply rapidly, causing extensive tissue damage and life-threatening sepsis and organ failure. V. vulnificus is also responsible for the majority of seafood-associated deaths worldwide.

Flesh-eating bacteria are considered opportunistic pathogens, meaning they do not usually produce serious illness in most normal, healthy individuals. People who are most at risk include infants and the elderly, and individuals with weakened immune systems due to diabetes, cancer chemotherapy, alcoholism, liver or kidney disease.

If you fall into these risk groups and have an open wound, you should refrain from swimming in warm waters where the flesh-eating bacteria has been found. Injuries sustained while in contact with water should be disinfected immediately. Early signs of infection occur within hours of exposure and may include swelling, redness, fever, and pain that seems unusually intense. Later signs of infection may include ulcers, blisters, pus, skin discoloration, and gastrointestinal distress.

If you suspect that you’ve been infected, it is imperative to get prompt medical care. The sooner intravenous antibiotics can be administrated, the better the chances of survival. Surgery, including amputation, is often required to remove necrotic tissue.

While on the rise, it should be emphasized that cases of flesh-eating bacteria remain very rare.

According to the Centers for Disease Control and Prevention, there are only 205 cases of V. vulnificus in the U.S. each year among the millions of people who enjoy swimming in lakes and oceans. But since one in seven people who contract the infection dies, people in high-risk groups should be vigilant.

Two major factors are behind the modest increase in flesh-eating bacteria cases in recent years. Global warming is expanding the breeding grounds for these warm water-loving bacteria; an increasing number of cases have been reported in midwestern states as far north as Kentucky and on the Eastern seaboard in Maryland and Delaware. Second, an increasing number of people are taking immunosuppressive medications that may leave them more vulnerable to opportunistic infection.

The views expressed in this content represent the perspective and opinions of the author and may or may not represent the position of Indiana University School of Medicine.

Bill Sullivan

Bill Sullivan is Showalter Professor in the Departments of Pharmacology & Toxicology and Microbiology & Immunology at the Indiana University School of Medicine. His research is centered on infectious disease and anti-infective agents.