Vibrio vulnificus

• Halophilic (salt-loving) marine pleomorphic Gram-negative rod that causes severe rapidly-progressing soft tissue infections

Background

Pathophysiology

• Polysaccharide capsule is resistant to phagocytosis and triggers cytokine release including TNF-alpha
• It can sequester iron from hemoglobin and highly-saturated transferrin

Epidemiology

• Mostly found in saltwater estuaries, associated with springtime plankton blooms
• Normal microbiotia of molluscs, including oysters and crabs

Risk Factors

• Cirrhosis
• Other liver disease
• Iron-overload states including hemochromatosis, hemolytic anemia, chronic renal failure
• Malignancy
• HIV
• Immunosuppressing medications

Clinical Presentation

• Presents as gastroenteritis, skin infection, and bacteremia in an immunocompromised patient (usually cirrhosis)
• 1 to 3 days following ingestion of oysters
• Severe, rapidly-progressing soft tissue infection
  • Erythematous lesions that develop into hemorrhagic bullae then necrotic ulcers
  • Metastatic cutaneous lesions develop at 36 hours
  • Often related to a wound contaminated with salt water, often in the Golf Coast
• Bacteremia is common
  • Associated with oyster consumption in 90% of cases
• 25% case-fatality rate, up to 50% in cases of bacteremia

Management

• Needs antibiotics, ideally early, as well as surgical debridement of the nectrotizing soft tissue infection
• Fluoroquinolones, third-generation cephalosporins, and doxycycline all work
• Should typically start with combination of third-generation cephalosporin and either ciprofloxacin or doxycycline

Prevention

• Patients with cirrhosis should avoid eating raw oysters