Noncholera Vibrio Infections
Noncholera vibrios include Vibrio parahaemolyticus, V. mimicus, V. alginolyticus, V. hollisae, and V. vulnificus; they may cause diarrhea, wound infection, or septicemia.
Noncholera vibrios are sometimes called nonagglutinable vibrios (ie, they do not agglutinate with serum from cholera patients). They typically inhabit warm salt water or mixed salt and fresh water (eg, in estuaries).
V. 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 US. 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 someone with chronic liver disease or immunodeficiency), can cross the intestinal mucosa without causing enteritis and cause septicemia with a high mortality rate; occasionally, otherwise healthy people develop such infections.
Enteric illness begins suddenly after a 15- to 24-h incubation period; manifestations include cramping abdominal pain, large amounts of watery diarrhea (stools may be bloody and contain PMNs), tenesmus, weakness, and sometimes nausea, vomiting, and low-grade fever. Symptoms subside spontaneously in 24 to 48 h.
Cellulitis can rapidly develop in contaminated wounds in some cases (typically those involving V. vulnificus) and progress to necrotizing fasciitis with typical hemorrhagic, bullous lesions.
V. vulnificus septicemia causes shock, bullous skin lesions, and often manifestations of disseminated intravascular coagulation (eg, thrombocytopenia, hemorrhage); mortality rate is high.
Noncholera Vibrio enteric infections can be treated with a single dose of ciprofloxacin 1 g po or doxycycline 300 mg po. 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, doxycycline 100 mg po q 12 h, with or without a 3rd-generation cephalosporin for severe wound infection or septicemia. Ciprofloxacin is an acceptable alternative.
Patients with necrotizing fasciitis require surgical debridement.
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.
Treat severe enteric infections with a single dose ciprofloxacin or doxycycline.
Treat wound infections with doxycycline; for severe infection, add a 3rd-generation cephalosporin.