Vibrio Vulnificus: Risk Factors, Symptoms, Treatment

Vibrio vulnificus can cause a terrible skin infection. It can cause skin blisters called bullae (which can be filled with blood). What's more worrisome is that it can lead to a severe infection in the blood.

Fortunately, it is quite rare. Every year in the US, people are infected along the East Coast and the Gulf Coast. In Florida in 2013, 41 were infected and 12 died.

Acquiring the disease, though rare, is unfortunately quite simple. A simple walk on the beach, a step on a sharp shell, and the bacteria in the warm seawater can enter.

The bacteria is found commonly in warm seawater. Warmer water increases the amount of Vibrio vulnificus found. It is only found in saltwater and brackish water.

What Kind of Disease Is Vulnificus?

The bacteria is a relative of cholera. Both cause vomiting and diarrhea. Cholera quickly spreads from person-to-person, causing epidemics, while there is no evidence vulnificus ever spreads from person to person. Vulnificus can cause a severe and blistering skin infection. It also can spread into the blood in those who are the most vulnerable; this can be rapidly fatal.

True flesh-eating bacteria are actually only strep A infections. Vulnificus infections look like strep but do not cause an infection that spreads in the skin as deeply as strep does. According to the CDC, multiple bacteria (including Vibrio) can cause necrotizing fasciitis, which is the medical term for flesh eating.

Symptoms

• Diarrhea and abdominal pain
• Fever, chills
• Very low blood pressure
• Blistering, warm, swollen, and reddened skin near where the bacteria entered. There can be bleeding and discharge associated with these blisters.

Who Is at Risk?

• Anyone who eats raw oysters or other shellfish
• Anyone with a cut exposed to warm seawater, especially in the Gulf of Mexico, but also in other areas along the East Coast of the United States

Men, particularly older men, appear to have a far greater risk of serious infection than women. Having any of the following conditions also puts you at higher risk:

• Liver disease
• People with a condition called hereditary hemochromatosis
• Alcoholism
• Diabetes
• Rheumatoid arthritis
• Thalassemia major
• Chronic kidney failure

The bacteria usually only causes severe disease — sepsis, or infection in the blood — in those at most risk. The mortality risk for those who develop severe sepsis can be as high as 50%.

How You Become Infected

Infections can happen from a walk on the beach. The bacteria can enter open wounds, such as those from stepping on sharp shells or glass. It is particularly associated with alcohol use. The infection can spread from the skin into the blood in those at risk. Vibrio can also cause skin infections when a wound comes into contact with raw or undercooked seafood and its juices or drippings.

Infection can also occur from eating raw or undercooked oysters from the Gulf Coast. It can also be found in Atlantic and Pacific waters. The infection can spread from the intestines into the blood in those at risk.

While people who eat oysters can get Vibrio, it doesn’t cause skin infections through this route—instead, symptoms are gastrointestinal. Both forms of transmission—through infection of a cut or wound, and by eating raw shellfish—can cause bloodstream infections and severe skin blistering.

Diagnosis

The bacteria can be found in wound or blood cultures. Stool testing is also possible, but requires labs to have a special medium — or plate — for the bacteria to grow and be identified.

Treatment

Because the disease can be so severe, treatment should not be delayed while awaiting organism confirmation. Treatment for severe cases requires hospitalization. It is often with the IV antibiotic ceftazidime and the antibiotic doxycycline. It sometimes can be treated with fluoroquinolones. The skin infection can be so severe that surgery is needed to debride it, or amputation may be required.

Prevention

Even oysters that are legally harvested can have Vibrio vulnificus. The FDA works with state officials to trace any infections to oyster beds. Work is being done to better identify what factors lead to growth and reduce the risk that oysters that are harvested carry the bacteria.

Here are some ways to avoid infection:

• Avoid eating raw or undercooked shellfish, particularly oysters (or avoid eating seafood altogether)
• Do not expose wounds to salt water (i.e., go wading in ocean with wounds on feet or legs), and do not handle shellfish if you have wounds on your hands
• Clean any wounds exposed to saltwater or shellfish thoroughly with soap and water