Vibrio vulnificus infection
Vibrio vulnificus is a gram-negative bacillus acquired by eating raw shellfish or through wound exposure to warm salt or brackish water, causing severe bullous skin and soft-tissue infection, necrotizing fasciitis, or primary septicemia, especially in patients with cirrhosis, hemochromatosis, or other liver disease. Even with prompt combination antibiotic therapy (doxycycline plus a third-generation cephalosporin) and emergent surgical debridement, mortality exceeds 30%.
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What this article covers
- Overview
Vibrio vulnificus is a gram-negative bacillus found in warm marine and brackish waters that causes a severe, rapidly progressive bullous skin and soft-tissue infection, necrotizing fasciitis, or primary septicemia.
- Epidemiology
Infection is acquired through ingestion of raw shellfish, especially oysters, or through skin injury sustained in warm salt water, such as the Gulf of Mexico, or in brackish water.
- Risk factors
Chronic liver disease, especially cirrhosis and hemochromatosis (iron overload), is the principal host risk factor, conferring susceptibility to both bloodstream infection and severe wound infection.
- Pathophysiology
Vibrio vulnificus enters through the gastrointestinal tract after ingestion of contaminated shellfish or directly through breaks in the skin exposed to contaminated water.
- Clinical features
Abrupt onset of fever and hypotension, often the earliest systemic signs of invasive infection.
- Differential diagnosis
Group A streptococcus (Streptococcus pyogenes) necrotizing fasciitis: lacks the raw-shellfish/warm-saltwater exposure history; treated with penicillin plus clindamycin once confirmed, rather than doxycycline plus a cephalosporin.
- Diagnosis
The diagnosis is confirmed by isolation of Vibrio vulnificus on blood culture, wound/tissue culture, or stool culture, in a patient with the characteristic exposure history (raw shellfish ingestion…
- Management
First, obtain emergent surgical assessment for debridement whenever necrotizing soft-tissue infection is suspected; surgical source control is as time-critical as antibiotics and should not be delayed for imaging or culture results.
- Complications
Necrotizing fasciitis with extensive soft-tissue loss, frequently requiring extensive debridement or amputation.
- Prognosis
Mortality exceeds 30% even with prompt antibiotic therapy and surgical debridement, reflecting the fulminant nature of infection in susceptible hosts.
- Prevention
Patients with cirrhosis or other chronic liver disease should be counseled to strictly avoid raw shellfish, particularly raw oysters, given the risk of potentially fatal infection.
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