Vibrio vulnificus is a virulent, gram-negative rod that can cause wound infections and primary septicemia. Vibrio vulnificus is endemic to the coast of the Gulf of Mexico, the Chesapeake Bay, and, to a lesser extent, the Atlantic and Pacific coasts of North America and Northern Europe.

Infection is contracted through sustaining a new scratch, inoculation of a pre-existing wound, or through ingestion of raw shellfish such as raw oysters (V. vulnificus is found in up to 10% of raw shellfish on the market in the United States). It is generally acquired in coastal areas (particularly the Gulf Coast) where it is part of the normal flora of seawater from warmer climates.

Cutaneous lesions develop at the site of a new or prior wound and can spread rapidly, varying in severity from a mild cellulitis to a life-threatening soft tissue infection, including myositis and necrotizing fasciitis. Tenosynovitis can occur after a laceration. Risk factors for severe V. vulnificus infection include pre-existing liver disease, in particular alcoholic liver disease and hemochromatosis, and a subset of chronic medical diseases, including lymphoma, rheumatoid arthritis, chronic renal failure, and diabetes mellitus.

One-third of patients either present with shock or develop shock during the first 12 hours of hospitalization. Mortality for primary V. vulnificus septicemia with hypotension is approximately 50%, and amputation results in 10% of cases.