Vibrio vulnificus

Vibrio vulnificus is a species of Gram-negative, motile, curved, rod-shaped bacteria in the genus Vibrio. Present in marine environments such as estuaries, brackish ponds, or coastal areas, V. vulnificus is closely related to V. cholerae, the causative agent of cholera.^[1],[2]

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Clinical features

Vibrio vulnificus causes an infection often incurred after eating seafood, especially oysters; the bacteria can also enter the body through open wounds when swimming or wading in infected waters,^[2] 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. Severe symptoms and even death can occur if the bacterium enters the bloodstream—something more common in people with compromised immune systems or liver disease.^[3]

Treatment

Vibrio vulnificus infection has a mortality rate of 50% with the majority of patients dying 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) were associated with an improved outcome.^[4] Prospective clinical trials are needed to confirm this finding, but in vitro data supports the supposition that this combination is synergistic against Vibrio vulnificus.

Vibrio vulnificus often causes large, disfiguring ulcers which require extensive debridement or even amputation.

Prognosis

The worst prognosis is in those patients who arrive at hospital in a state of shock. Total mortality in treated patients is around 33%.^[4]

Those patients who are especially vulnerable, including those with 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.^[5] According to the 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 is believed to have a protective effect against V. vulnificus.^[6]

Historical

Health officials clearly identified strains of V. vulnificus infections among refugees from New Orleans due to the flooding there caused by Hurricane Katrina.^[7]

References