Which organism is most commonly associated with large-volume watery diarrhea and dehydration in outbreaks?

Which organism is most commonly associated with large-volume watery diarrhea and dehydration in outbreaks?

• A. Escherichia coli enterotoxigenic
• B. Vibrio cholerae
• C. Shigella dysenteriae
• D. Salmonella enteritidis

Answer: (B)

Massive secretory diarrhea is driven by a toxin that makes the gut secrete water and chloride, leading to very large stools and rapid dehydration. Vibrio cholerae produces cholera toxin, which ADP-ribosylates a Gs protein and continuously activates adenylate cyclase, raising cAMP in enterocytes. This keeps chloride channels open and pushes chloride (and with it, water and electrolytes) into the intestinal lumen. The result is the classic profuse, watery “rice-water” stool seen in cholera outbreaks, with dehydration advancing quickly if untreated. Outbreaks are especially linked to drinking contaminated water or eating contaminated seafood in areas with poor sanitation. Other organisms listed can cause watery diarrhea or inflammatory diarrhea, but not the same pattern of colossal fluid loss. Enterotoxigenic E. coli also makes a secretory-type diarrhea via its toxins but typically not the extreme volumes seen in cholera. Shigella causes invasive disease with fever and bloody, mucus-filled stools. Salmonella enteritidis often causes gastroenteritis with fever and abdominal cramps, but not the hallmark massive watery diarrhea of cholera. In this context, Vibrio cholerae is the organism most closely associated with large-volume watery diarrhea and dehydration in outbreaks.

Massive secretory diarrhea is driven by a toxin that makes the gut secrete water and chloride, leading to very large stools and rapid dehydration. Vibrio cholerae produces cholera toxin, which ADP-ribosylates a Gs protein and continuously activates adenylate cyclase, raising cAMP in enterocytes. This keeps chloride channels open and pushes chloride (and with it, water and electrolytes) into the intestinal lumen. The result is the classic profuse, watery “rice-water” stool seen in cholera outbreaks, with dehydration advancing quickly if untreated. Outbreaks are especially linked to drinking contaminated water or eating contaminated seafood in areas with poor sanitation.

Other organisms listed can cause watery diarrhea or inflammatory diarrhea, but not the same pattern of colossal fluid loss. Enterotoxigenic E. coli also makes a secretory-type diarrhea via its toxins but typically not the extreme volumes seen in cholera. Shigella causes invasive disease with fever and bloody, mucus-filled stools. Salmonella enteritidis often causes gastroenteritis with fever and abdominal cramps, but not the hallmark massive watery diarrhea of cholera. In this context, Vibrio cholerae is the organism most closely associated with large-volume watery diarrhea and dehydration in outbreaks.