Vibrio vulnificus is a species of Gram-negative, motile, curved, rod-shaped bacteria of the genus Vibrio. Present in marine environments such as estuaries, brackish ponds, or coastal areas, V. vulnificus is related to V. cholerae, the causative agent of cholera., Infection with V. vulnificus leads to rapidly expanding cellulitis or septicemia. It was first isolated in 1976.
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Vibrio vulnificus causes an infection often incurred after eating seafood, especially raw or undercooked oysters; the bacteria can also enter the body through open wounds when swimming or wading in infected waters, or via puncture wounds from the spines of fish such as tilapia.
Symptoms include vomiting, diarrhea, abdominal pain, and a blistering dermatitis that is sometimes mistaken for pemphigus or pemphigoid.
V. vulnificus is eighty times more likely to spread into the blood stream in people with compromised immune systems, especially those with chronic liver disease. When this happens, severe symptoms including blistering skin lesions, septic shock, and even death can occur. This severe infection may occur regardless of whether the infection began via contaminated food or via an open wound.
Vibrio vulnificus wound infections have a mortality of approximately 25%. In patients in whom the infection worsens into septicemia, typically following ingestion, the mortality rate rises dramatically to 50%. The majority of these patients die within the first 48 hours of infection. The optimal treatment is not known, but, in one retrospective study of 93 patients in Taiwan, use of a third-generation cephalosporin and a tetracycline (e.g., ceftriaxone and doxycycline, respectively) were associated with an improved outcome. Prospective clinical trials are needed to confirm this finding, but in vitro data support the supposition this combination is synergistic against Vibrio vulnificus. Similarly, the American Medical Association and the Centers for Disease Control and Prevention recommend treating the patient with a quinolone or intravenous doxycycline with ceftazidime.
V. vulnificus often causes large, disfiguring ulcers that require extensive debridement or even amputation.
V. vulnificus is commonly found in the Pacific Northwest.
The worst prognosis is in those patients who arrive at hospital in a state of shock. Total mortality in treated patients (ingestion and wound) is around 33%.
Patients especially vulnerable are those with liver disease (especially chirrhosis and hepatitis) or immunocompromised states (cancer, bone marrow suppression, HIV, diabetes, etc.). With these cases, V. vulnificus usually enters the bloodstream where it may cause fever and chills, septic shock (with sharply decreased blood pressure), and blistering skin lesions. According to the Centers for Disease Control and Prevention (CDC), about half of those who contract blood infections die.
Vibrio vulnificus infections also disproportionately affect males; 85% of those who develop endotoxic shock from the bacteria are male. Females who have had an oophorectomy experienced increased mortality rates, as estrogen has been shown experimentally to have a protective effect against V. vulnificus.
The pathogen was first isolated in 1976 from a series of blood culture samples submitted to the CDC in Atlanta. It was described as a "lactose-positive vibrio". It was subsequently given the name Beneckea vulnifica, and finally Vibrio vulnificus by Farmer in 1979.
Health officials clearly identified strains of V. vulnificus infections among evacuees from New Orleans due to the flooding there caused by Hurricane Katrina.