Which organism is typically spread by the fecal-oral route?

Which organism is typically spread by the fecal-oral route?

• A. Shigella
• B. Salmonella
• C. Campylobacter jejuni
• D. Escherichia coli

Answer: (A)

Fecal-oral transmission is most characteristic of Shigella because it has an extremely low infectious dose and spreads readily from person to person through contaminated hands, food, or water. Even a tiny number of organisms can cause illness, which explains why outbreaks occur in settings with close contact and poor hygiene, such as daycare centers. The illness typically presents with inflammatory diarrhea that can include blood and mucus (dysentery), reflecting the organism’s invasion of the colonic mucosa. Salmonella can also spread via the fecal-oral route, but it is more commonly linked to ingestion of contaminated animal products like undercooked poultry, eggs, or dairy, and often requires a somewhat larger bacterial dose. Campylobacter jejuni is predominantly a foodborne pathogen associated with undercooked poultry and unpasteurized milk, with fecal-oral transmission as a route but not as the defining pattern. Escherichia coli includes various strains that cause diarrhea through fecal-oral spread as well, but Shigella is the classic example emphasized for direct human-to-human fecal-oral transmission.

Fecal-oral transmission is most characteristic of Shigella because it has an extremely low infectious dose and spreads readily from person to person through contaminated hands, food, or water. Even a tiny number of organisms can cause illness, which explains why outbreaks occur in settings with close contact and poor hygiene, such as daycare centers. The illness typically presents with inflammatory diarrhea that can include blood and mucus (dysentery), reflecting the organism’s invasion of the colonic mucosa.

Salmonella can also spread via the fecal-oral route, but it is more commonly linked to ingestion of contaminated animal products like undercooked poultry, eggs, or dairy, and often requires a somewhat larger bacterial dose. Campylobacter jejuni is predominantly a foodborne pathogen associated with undercooked poultry and unpasteurized milk, with fecal-oral transmission as a route but not as the defining pattern. Escherichia coli includes various strains that cause diarrhea through fecal-oral spread as well, but Shigella is the classic example emphasized for direct human-to-human fecal-oral transmission.