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The term “flesh-eating bacteria” refers to bacteria that cause necrotizing fasciitis that destroys the soft tissue, particularly the fascial layer underneath the skin. Individuals with suspected cases should be treated with antibiotics immediately, as patients can die within a day or two of developing symptoms, according to the CDC.

“V vulnificus wound infections have a short incubation period and are characterized by necrotizing skin and soft tissue infection, with or without hemorrhagic bullae,” according to a warning statement issued by the Louisiana Department of Health. The warning was issued in July 2025 after an increase in severe cases, with 17 confirmed in the state so far in 2025 alone, including four deaths compared to an average of seven cases and one death annually over the past decade.

“Most cases of necrotizing fasciitis are due to group A streptococcus,” said Shirin Mazumder, MD, infectious diseases specialist in Memphis, Tennessee, in an interview. “Vibrio vulnificus is a rare cause of necrotizing fasciitis that can be acquired when open wounds come in contact with warm salt water or brackish water, or through ingestion of raw or undercooked seafood,” Mazumder told Medscape Medical News. “Vibrio vulnificus needs salt water to survive, so it be found in brackish water where freshwater and seawater mix,” she said. 

Most of the Louisiana cases (75%) involved wound exposure to sea water, according to the statement. Key symptoms of infection also include watery diarrhea, abdominal pain, nausea, vomiting, and fever.

Diagnosis is based on identification of V vulnificus in the stool, wound, or blood of a symptomatic patient, but suspected cases from water exposure should begin treatment with antibiotics immediately, without waiting for test results, according to the CDC. The CDC currently recommends antibiotic treatment with a third-generation cephalosporin such as ceftazidime, plus doxycycline, as a first-line treatment.

Individuals with V vulnificus infections may need aggressive debridement to remove necrotic tissue, according to the CDC; in extreme cases, amputation of an infected limb is necessary. 

When to Worry, What to Do

“Individuals that have contact strictly with freshwater should not be concerned about exposure,” Mazumder emphasized. “The risk of vibriosis can be decreased by avoiding contact of any open wounds with salt water or brackish water, covering open wounds if there is anticipated contact with coastal water, and immediately washing any open wounds with soap and water that may have come in contact with salt or brackish water,” she said.

The Louisiana Department of Health encourages individuals to reduce their risk for V vulnificus infection by avoiding coastal water activities if they have open wounds. Individuals with immunocompromising conditions, as well as those with diabetes or liver disease, may be especially vulnerable to infection, and the risk for exposure to V vulnificus may be greater given increased water temperatures and recent heat waves, flooding, and storms along the Gulf Coast, the Louisiana Department of Health experts wrote in the statement. 

Although most V vulnificus infections are reported in states along the Gulf Coast, the CDC issued an official Health Advisory in the summer of 2023, when a measured above-average coastal sea surface temperatures and heat waves coincided with severe and fatal V vulnificus infectious in states along the East Coast, including New York, North Carolina, and Connecticut.

“An increase in Vibrio vulnificus cases can be attributed to warmer weather, rising coastal water temperatures and extreme weather events such as flooding, hurricanes and storms which can force coastal waters inland,” Mazumder told Medscape Medical News. “Most cases of Vibrio vulnificus infections are found along the Gulf states; however, more cases are being identified in northeastern states due to increasing water temperature,” she noted. 

Mazumder echoed the CDC’s recommendation for immediate initiation of antibiotics in suspected V vulnificus infections.

“A third-generation cephalosporin in combination with either a tetracycline or fluoroquinolone should be started promptly, and antibiotic therapy can be tailored once susceptibility data is available,” said Mazumder. “In addition, supportive care is necessary, and evaluation for immediate surgical debridement should be considered in those with a skin and soft tissue infection,” she said. Appropriate diagnostic specimens should be obtained, including blood cultures, wound cultures and stool testing in patients who have diarrhea.

Most importantly, V vulnificus is a reportable infection, so clinicians who encounter cases must contact their local health departments, Mazumder added.

Mazumder had no financial conflicts to disclose.