Noncholera vibrios include the gram-negative bacteria Vibrio parahaemolyticus, V. mimicus, V. alginolyticus, V. hollisae, and V. vulnificus
Noncholera vibrios are sometimes called nonagglutinable vibrios (ie, they do not agglutinate with serum from patients with cholera). They typically inhabit warm salt water or mixed salt and fresh water (eg, in estuaries).
Vibrio parahaemolyticus, V. mimicus, and V. hollisae usually cause food-borne outbreaks of diarrhea, typically involving inadequately cooked seafood (usually shellfish).
V. parahaemolyticus infections typically occur in Japan and in coastal areas of the United States. The organisms damage intestinal mucosa but do not produce enterotoxin or invade the bloodstream. Also, wound infection may develop when contaminated warm seawater enters a minor wound.
V. alginolyticus and V. vulnificus can cause serious wound infection; neither causes enteritis. V. vulnificus, when ingested by a compromised host (often people with chronic liver disease or immunodeficiency), can cross the intestinal mucosa without causing enteritis and cause septicemia with a high case fatality rate; occasionally, otherwise healthy people develop such infections.
Symptoms and Signs of Noncholera Vibrio Infections
Enteric illness begins suddenly after a 15- to 24-hour incubation period; manifestations include cramping abdominal pain, large amounts of watery diarrhea (stools may be bloody and contain polymorphonuclear leukocytes), tenesmus, weakness, and sometimes nausea, vomiting, and low-grade fever. Symptoms subside spontaneously in 24 to 48 hours.
Cellulitis can rapidly develop in contaminated wounds in some cases (typically those involving V. vulnificus) and progress to necrotizing soft-tissue infection with typical hemorrhagic, bullous lesions.
V. vulnificus septicemia causes shock, bullous skin lesions, and often manifestations of disseminated intravascular coagulation (eg, thrombocytopenia, hemorrhage); case fatality rate is high.
Diagnosis of Noncholera Vibrio Infections
Cultures
Noncholera Vibrio wound and bloodstream infections are readily diagnosed with routine cultures.
When enteric infection is suspected, Vibrio organisms can be cultured from stool on thiosulfate citrate bile salts sucrose medium. Contaminated seafood also yields positive cultures.
Treatment of Noncholera Vibrio Infections
Antibiotics and often debridement for wound infection
Noncholera Vibrio enteric infections can be treated with a single oral dose of 1 of the following:
However, generally, such treatment is not necessary because the infection is self-limited, although treatment may be considered in severe cases.
If diarrhea is present, close attention to volume repletion and replacement of lost electrolytes are needed.
For wound infections, antibiotics are used—typically, oral doxycycline often with a third-generation cephalosporin for severe wound infection or septicemia. Ciprofloxacin is an acceptable alternative.
Patients with necrotizing soft-tissue infection require surgical debridement.
Key Points
Noncholera vibrios may cause diarrhea, wound infection, or septicemia, depending on the species and mode of exposure.
Diagnose using cultures of stool, wound, or blood as appropriate.
Necrotizing soft-tissue infection requires surgical debridement.
