Bacterial Diarrhea & Dysentery MCQ Quiz | Gastrointestinal Infections

1. A 6-year-old child presents with bloody diarrhea, abdominal cramps, and is later diagnosed with Hemolytic Uremic Syndrome (HUS). Which E. coli pathotype is most likely responsible?

2. The primary mechanism of action of cholera toxin leading to profuse “rice-water” stools is:

3. Which key virulence factor of Shigella spp. allows for its intracellular spread from one enterocyte to an adjacent one?

4. A patient develops pseudomembranous colitis after a course of clindamycin. The condition is caused by toxins produced by which organism?

5. Which of the following bacterial diarrheas is most characteristically associated with consumption of undercooked poultry?

6. A patient with non-typhoidal Salmonella gastroenteritis is generally managed with:

7. Which term describes diarrhea characterized by blood and mucus in the stool, often accompanied by fever, abdominal cramps, and tenesmus?

8. A traveler returns from Southeast Asia with profuse, non-bloody, watery diarrhea. The stool culture is performed on thiosulfate-citrate-bile salts-sucrose (TCBS) agar. Yellow colonies are observed. What is the most likely pathogen?

9. The emetic (vomiting) form of Bacillus cereus food poisoning is caused by a heat-stable toxin and is most commonly associated with consumption of:

10. Guillain-Barré syndrome is a potential post-infectious complication most strongly associated with which of the following enteric pathogens?

11. Yersinia enterocolitica infection can mimic acute appendicitis and is often associated with the consumption of:

12. Which of the following is a non-invasive, toxin-mediated cause of traveler’s diarrhea, producing heat-labile (LT) and heat-stable (ST) toxins?

13. A key characteristic of Shigella that distinguishes it from Salmonella in a laboratory setting is:

14. What is the cornerstone of management for a patient with severe dehydration due to cholera?

15. The “rose spots” on the abdomen are a characteristic, though not always present, sign of which bacterial infection?

16. Which organism requires a microaerophilic environment (low O2, high CO2) and incubation at 42°C for optimal growth in culture?

17. Antibiotic use is a major risk factor for C. difficile infection because it:

18. Enteroaggregative E. coli (EAEC) causes persistent watery diarrhea, especially in children, through a mechanism involving:

19. Which of the following statements about Shigella infection is TRUE?

20. The pathogenesis of enteropathogenic E. coli (EPEC) involves:

21. A patient presents with explosive watery diarrhea after consuming raw oysters. The most likely causative agent is:

22. The primary site of invasion for Salmonella Typhi, leading to systemic disease, is:

23. Reactive arthritis (Reiter’s syndrome) is a known sequela of infection with several enteric pathogens, including:

24. What is the standard diagnostic test for Clostridioides difficile infection in a symptomatic patient?

25. A patient develops watery diarrhea, fever, and abdominal cramps. A stool sample examined under a microscope reveals S-shaped or “gull-wing” gram-negative rods. Which pathogen is most likely?