Vibrio vulnificus infection: diagnosis and treatment.(Disease/Disorder overview)(Clinical report)

Publication: American Family Physician

Publication Date: 15-AUG-07

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COPYRIGHT 2007 American Academy of Family Physicians

Vibrio vulnificus infection is the leading cause of death related to seafood consumption in the United States. This virulent, gram-negative bacterium causes two distinct syndromes. The first is an overwhelming primary septicemia caused by consuming raw or undercooked seafood, particularly raw oysters. The second is a necrotizing wound infection acquired when an open wound is exposed to warm seawater with high concentrations of V. vulnificus. Most patients, including those with primary infection, develop sepsis and severe cellulitis with rapid development to ecchymoses and bullae. In severe cases, necrotizing fasciitis can develop. Case-fatality rates are greater than 50 percent for primary septicemia and about 15 percent for wound infections. Treatment of V. vulnificus infection includes antibiotics, aggressive wound therapy, and supportive care. Most patients who acquire the infection have at least one predisposing immunocompromising condition. Physician awareness of risk factors for V. vulnificus infection combined with prompt diagnosis and treatment can significantly improve patient outcomes. (Am Fam Physician 2007;76:539-44, 546. Copyright [C] 2007 American Academy of Family Physicians.)

Vibrio vulnificus is a species of gramnegative, motile, curved bacterium that is part of the Vibrio genus and the Vibrionaceae family. Other members of this family include V. cholerae (rare in the United States) and V. parahaemolyticus, both of which cause acute gastrointestinal illness characterized by severe diarrhea. Unlike other members of this family, V. vulnificus infection is extremely invasive. Even with prompt diagnosis and aggressive therapy, the case-fatality rate is 30 to 40 percent. (1-3)

Epidemiology

V. vulnificus is common in warm seawater and thrives in water temperatures greater than 68[degrees]F (20[degrees]C). The organism is not associated with pollution or fecal waste. The taste, appearance, and odor of seafood are not affected by V. vulnificus contamination, and proper cooking methods readily kill the organism. Although it is found in all coastal waters of the United States, most V. vulnificus infections are attributed to consuming raw oysters harvested in the Gulf of Mexico during the summer. (2) Because these oysters are shipped throughout the United States, infections are not limited to endemic areas. (4)

Approximately 25 percent of V. vulnificus infections are caused by direct exposure of an open wound to warm seawater containing the organism. Exposure typically occurs when the patient is participating in water activities such as boating, fishing, or swimming. Infections are occasionally attributed to contact with raw seafood or marine wildlife. (1)

V. vulnificus is one of the few foodborne illnesses with an increasing incidence. The Centers for Disease Control and Prevention estimates that the average annual incidence of all Vibrio infections increased by 41 percent between 1996 and 2005. (5) In 2004, V. vulnificus was documented in 92 infections; 64 patients with the infection had septicemia, and 28 patients had wound infections. (1) These data emphasize the need for physicians to familiarize themselves with the risk factors and clinical characteristics of V. vulnificus infection.

Risk Factors

Table 1 (2) includes risk factors for developing V. vulnificus infection. After the organism enters the body, several factors determine if significant illness develops. Patients with immunocompromising conditions, especially alcoholic liver disease...

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