The term “flesh-eating bacteria” describes necrotizing fasciitis, a severe soft-tissue infection that destroys tissue quickly. In Florida’s coastal environment, the most common cause of this waterborne illness is the bacterium Vibrio vulnificus. This microbe is naturally present in the state’s marine and brackish waters. Understanding where and when this organism thrives helps mitigate the risk of infection.
The Specific Organism and Its Habitat
Vibrio vulnificus is a naturally occurring marine bacterium acquired directly from the aquatic environment or contaminated seafood. Its presence is linked to specific environmental conditions, particularly water temperature and salinity.
The organism thrives in warm, low-salinity coastal waters, reaching its highest concentrations when temperatures exceed 68°F (20°C). This makes May through October the peak season for its abundance and for human infections in Florida. The bacteria are most commonly found in brackish water environments, such as estuaries and bays, where freshwater runoff mixes with seawater.
The organism does not tolerate high salt levels, concentrating it in estuarine systems rather than the open ocean. These warmer, less salty areas provide the ideal niche for Vibrio vulnificus to proliferate. The bacteria also naturally associate with filter-feeding shellfish, like oysters, which concentrate the microbes as they feed.
Geographic Concentration and Exposure Points in Florida
The bacteria can be found statewide in any coastal region meeting the required temperature and salinity criteria. Florida’s extensive coastline, including the Gulf of Mexico and Atlantic Ocean, offers large areas of suitable habitat. The Gulf Coast and areas with significant estuaries, such as the Indian River Lagoon, report a notable number of cases. Storm events, like hurricanes, can also increase exposure by pushing brackish waters inland and causing injuries that act as entry points.
Direct Water Contact
One primary way people become exposed is through direct water contact. The bacteria enter the body through an open wound, cut, scrape, piercing, or tattoo. This risk is heightened when wading or swimming in warm, brackish waters, especially where water meets sediment.
Contaminated Seafood Consumption
The second major exposure route is through the consumption of contaminated seafood. Foodborne illness is associated with eating raw or undercooked shellfish, particularly oysters harvested from Florida waters. Oysters are filter feeders and naturally accumulate the bacteria without appearing contaminated.
Essential Prevention Measures
Preventing infection involves avoiding exposure in known habitats and mitigating consumption risks. Individuals with open wounds, cuts, or scrapes should avoid contact with warm salt or brackish water and raw seafood drippings. If exposure occurs, the wound should be thoroughly washed immediately with soap and clean running water.
Safe Shellfish Preparation
Thorough cooking of all shellfish, particularly oysters, eliminates the risk of foodborne infection. In-shell shellfish must be boiled until the shells open, then boiled for five additional minutes, or steamed until they open, then cooked for nine more minutes. Shucked oysters should be boiled for at least three minutes or fried for a minimum of ten minutes at 375°F.
High-Risk Individuals
The risk of severe infection is higher for immunocompromised individuals, such as those with chronic liver disease or diabetes. These high-risk individuals should avoid eating raw shellfish and exercise caution when handling raw seafood or participating in water activities. If symptoms like fever, chills, abdominal pain, or a painful, swollen wound appear after potential exposure, immediate medical attention is necessary.