Wednesday, December 15, 2010

Diarrhea After Eating Raw Oysters

A 57-year-old fisherman with a history of alcoholism is hospitalized in Gulfport, Mississippi with a 1-day history of severe, watery diarrhea after eating several raw oysters. He is badly dehydrated on admission, and within 12 hours, he becomes severely hypotensive and dies. Which of the following pathogens is the most likely cause of this man's death? 

                A. Citrobacter diversus 
                B. Enterotoxigenic E. coli 
                C. Providencia stuartii 
                D. Vibrio cholerae 
                E. Vibrio vulnificus 


         The correct answer is E.Vibrio vulnificus is an extremely invasive organism, producing a septicemia in patients after eating raw shellfish, or causing wound infections, cellulitis, fasciitis, and myositis after exposure to seawater or after cleaning shellfish. Patients at high risk for septicemia include those with liver disease, congestive heart failure, diabetes mellitus, renal failure, hemochromatosis, and immunosuppression. 

         Citrobacter diversus(choice A) produces neonatal meningitis and can be frequently cultured from the umbilicus. 

         Enterotoxigenic E. coli(choice B) produces the classic traveler's diarrhea. The toxin is ingested in water and salads. The incubation period is approximately 12 hours. The diarrhea is non-inflammatory and treatment is supportive. 

         Providencia stuartii(choice C) is a gram-negative rod related to Proteus. It is a common cause of nosocomial bacteremia in nursing home patients with chronic catheterization. 

         Vibrio cholerae(choice D) produces a non-invasive, non-inflammatory, high-volume secretory diarrhea that is toxin-mediated.