MCQ Quiz: Management of C. Diff

Clostridioides difficile infection (CDI) is a significant healthcare-associated infection and a direct consequence of antibiotic-induced disruption of the normal gut flora. As a pharmacist, you are on the front lines of both preventing CDI through robust antimicrobial stewardship and treating it with evidence-based pharmacotherapy. A deep understanding of the risk factors, diagnosis, and the evolving treatment landscape for CDI is a core competency, as detailed in the Patient Care 4 curriculum’s module on “Management of Gastrointestinal Infections and C. Diff”. This quiz will test your knowledge of this challenging but manageable infection.

1. What is the most significant and modifiable risk factor for developing Clostridioides difficile infection (CDI)?

• a. Advanced age
• b. Exposure to antibiotics
• c. Use of proton pump inhibitors
• d. A recent surgical procedure

Answer: b. Exposure to antibiotics

2. The primary pathogenic mechanism of C. difficile involves the production of:

• a. A thick biofilm that protects it from antibiotics.
• b. Endospores that are resistant to heat and acid.
• c. Toxin A (an enterotoxin) and Toxin B (a cytotoxin).
• d. A capsule that prevents phagocytosis.

Answer: c. Toxin A (an enterotoxin) and Toxin B (a cytotoxin).

3. Which of the following is the recommended first-line treatment for an initial episode of non-severe CDI according to the latest guidelines?

• a. Oral Metronidazole
• b. IV Vancomycin
• c. Oral Fidaxomicin
• d. Oral Loperamide

Answer: c. Oral Fidaxomicin

4. What is the most important initial step in managing a patient newly diagnosed with CDI?

• a. Start oral vancomycin immediately.
• b. Place the patient on a clear liquid diet.
• c. Assess for and discontinue the offending antibiotic agent, if possible.
• d. Administer an anti-motility agent.

Answer: c. Assess for and discontinue the offending antibiotic agent, if possible.

5. Why is IV vancomycin NOT effective for treating CDI?

• a. It has poor penetration into the gastrointestinal tract lumen.
• b. It does not have activity against C. difficile.
• c. It causes severe nephrotoxicity when used for this indication.
• d. It is significantly more expensive than oral vancomycin.

Answer: a. It has poor penetration into the gastrointestinal tract lumen.

6. The “Management of Gastrointestinal Infections and C. Diff” is a specific learning module in which course?

• a. PHA5784C Patient Care 4
• b. PHA5104 Sterile Compounding
• c. PHA5703 Pharmacy Law and Ethics
• d. PHA5878C Patient Care 3

Answer: a. PHA5784C Patient Care 4

7. A patient is classified as having a “severe” initial episode of CDI based on which of the following criteria?

• a. Watery diarrhea (3-4 stools per day).
• a. WBC ≥ 15,000 cells/mm³ OR SCr ≥ 1.5 times baseline.
• c. Mild abdominal cramping.
• d. A positive stool test for C. difficile.

Answer: b. WBC ≥ 15,000 cells/mm³ OR SCr ≥ 1.5 times baseline.

8. For a patient experiencing their first recurrence of CDI, which of the following is an appropriate treatment option?

• a. A standard 10-day course of oral metronidazole.
• b. A tapered and/or pulsed regimen of oral vancomycin.
• c. A 3-day course of oral vancomycin.
• d. IV ceftriaxone.

Answer: b. A tapered and/or pulsed regimen of oral vancomycin.

9. Bezlotoxumab is a monoclonal antibody used in the management of CDI. What is its role?

• a. It is a first-line agent for treating an initial, non-severe episode.
• b. It is used to prevent the recurrence of CDI in high-risk patients.
• c. It treats fulminant CDI.
• d. It replaces the need for antibiotics.

Answer: b. It is used to prevent the recurrence of CDI in high-risk patients.

10. What is the most effective method of hand hygiene for preventing the spread of C. difficile spores?

• a. Using an alcohol-based hand sanitizer.
• b. Hand washing with soap and water.
• c. Wearing sterile gloves at all times.
• d. Wiping hands with a dry paper towel.

Answer: b. Hand washing with soap and water.

11. Which class of antibiotics carries the highest risk for inducing a C. difficile infection?

• a. Tetracyclines
• b. Macrolides
• c. Aminoglycosides
• d. Fluoroquinolones and clindamycin

Answer: d. Fluoroquinolones and clindamycin

12. A patient with fulminant CDI characterized by hypotension and ileus should be treated with:

• a. Oral fidaxomicin alone.
• b. High-dose oral vancomycin plus IV metronidazole.
• c. Oral metronidazole alone.
• d. An anti-motility agent like loperamide.

Answer: b. High-dose oral vancomycin plus IV metronidazole.

13. Fidaxomicin has been shown to be superior to oral vancomycin in what aspect of CDI management?

• a. It has a faster onset of action.
• b. It is less expensive.
• c. It results in lower rates of CDI recurrence.
• d. It has better oral bioavailability.

Answer: c. It results in lower rates of CDI recurrence.

14. What is the mechanism of action of fidaxomicin?

• a. It inhibits bacterial cell wall synthesis.
• b. It inhibits bacterial RNA polymerase.
• c. It inhibits bacterial DNA gyrase.
• d. It neutralizes Toxin B.

Answer: b. It inhibits bacterial RNA polymerase.

15. A fecal microbiota transplant (FMT) is a highly effective option for which of the following patients?

• a. A patient with an initial, non-severe CDI.
• b. A patient with multiple recurrent CDI episodes who has failed standard pharmacotherapy.
• c. A patient with antibiotic-associated diarrhea not caused by C. difficile.
• d. A patient with traveler’s diarrhea.

Answer: b. A patient with multiple recurrent CDI episodes who has failed standard pharmacotherapy.

16. What is the standard oral dose of vancomycin for treating a non-severe CDI?

• a. 500 mg four times daily
• b. 125 mg twice daily
• c. 250 mg twice daily
• d. 125 mg four times daily

Answer: d. 125 mg four times daily

17. The microbiology of Clostridium species is a topic within the Patient Care 2 curriculum.

• a. True
• b. False

Answer: a. True

18. Why should anti-motility agents like loperamide be avoided in patients with significant CDI?

• a. They can increase the risk of toxic megacolon by retaining the bacterial toxins.
• b. They are not effective for diarrhea caused by CDI.
• c. They have a severe interaction with vancomycin.
• d. They are too expensive.

Answer: a. They can increase the risk of toxic megacolon by retaining the bacterial toxins.

19. A patient’s stool sample is positive for the C. difficile gene via NAAT but negative for toxin via EIA. The patient is asymptomatic. What is the appropriate action?

• a. Treat with a 10-day course of oral vancomycin.
• b. Treat with a 14-day course of oral fidaxomicin.
• c. No treatment is needed; this represents asymptomatic colonization.
• d. Start bezlotoxumab infusion.

Answer: c. No treatment is needed; this represents asymptomatic colonization.

20. An active learning session on GI infections, including C. difficile, is part of the Patient Care 4 course.

• a. True
• b. False

Answer: a. True

21. The use of which medication class is considered a risk factor for CDI, possibly by altering the gut microbiome or pH?

• a. Beta-blockers
• b. Statins
• c. Proton Pump Inhibitors (PPIs)
• d. NSAIDs

Answer: c. Proton Pump Inhibitors (PPIs)

22. Bezlotoxumab works by what mechanism?

• a. It is a potent antibiotic that kills C. difficile.
• b. It is a monoclonal antibody that binds to and neutralizes C. difficile Toxin B.
• c. It restores the normal gut flora.
• d. It inhibits spore germination.

Answer: b. It is a monoclonal antibody that binds to and neutralizes C. difficile Toxin B.

23. The main reason for the high recurrence rate of CDI is:

• a. The bacteria rapidly developing resistance to vancomycin.
• b. The failure of antibiotics to eradicate the dormant, resistant spore form of the organism.
• c. Patient non-adherence to therapy.
• d. Reinfection from contaminated food.

Answer: b. The failure of antibiotics to eradicate the dormant, resistant spore form of the organism.

24. The diagnosis of CDI requires:

• a. The presence of diarrhea only.
• b. A positive stool test only.
• c. The presence of diarrhea (or ileus/megacolon) AND a positive stool test for C. difficile toxins or a toxigenic strain.
• d. A history of antibiotic use only.

Answer: c. The presence of diarrhea (or ileus/megacolon) AND a positive stool test for C. difficile toxins or a toxigenic strain.

25. A pharmacist’s role in preventing CDI includes:

• a. Promoting antimicrobial stewardship to avoid unnecessary antibiotic use.
• b. Recommending the narrowest spectrum agent appropriate for an infection.
• c. Advocating for the shortest effective duration of antibiotic therapy.
• d. All of the above.

Answer: d. All of the above.

26. Which of the following is NOT a first-line treatment for an initial episode of CDI?

• a. Fidaxomicin 200 mg PO BID for 10 days.
• b. Vancomycin 125 mg PO QID for 10 days.
• c. Metronidazole 500 mg PO TID for 10 days.
• d. All are acceptable first-line options.

Answer: c. Metronidazole 500 mg PO TID for 10 days.

27. What is a key structural feature of C. difficile that makes it difficult to eliminate from the hospital environment?

• a. Its thick peptidoglycan cell wall.
• b. Its ability to form resilient spores.
• c. Its outer membrane containing lipopolysaccharide.
• d. Its flagella, allowing for rapid movement.

Answer: b. Its ability to form resilient spores.

28. A vancomycin taper/pulse regimen is used for recurrent CDI to:

• a. Gradually kill off vegetative cells that germinate from spores during the drug-free intervals.
• b. Reduce the side effects of vancomycin.
• c. Decrease the cost of treatment.
• d. Make the regimen easier for the patient to remember.

Answer: a. Gradually kill off vegetative cells that germinate from spores during the drug-free intervals.

29. The term “pseudomembranous colitis” refers to:

• a. The severe inflammation and formation of plaques on the colon wall characteristic of severe CDI.
• b. A type of inflammatory bowel disease.
• c. A side effect of oral vancomycin.
• d. A viral infection of the colon.

Answer: a. The severe inflammation and formation of plaques on the colon wall characteristic of severe CDI.

30. The management of CDI is a lecture within the GI Infections module.

• a. True
• b. False

Answer: a. True

31. Fidaxomicin has a narrower spectrum of activity than vancomycin, which is advantageous because:

• a. It is less effective against C. difficile.
• b. It causes less disruption to the normal anaerobic gut flora, like Bacteroides.
• c. It has more drug interactions.
• d. It is a bactericidal agent.

Answer: b. It causes less disruption to the normal anaerobic gut flora, like Bacteroides.

32. A patient has their third episode of CDI in six months. This is defined as:

• a. An initial infection
• b. A first recurrence
• c. A multiply recurrent infection
• d. A healthcare-associated infection

Answer: c. A multiply recurrent infection

33. What is the role of the pharmacist in managing a patient receiving bezlotoxumab?

• a. To administer the IV infusion.
• b. To ensure it is given concurrently with a standard-of-care antibiotic for CDI.
• c. To counsel the patient that it is a one-time infusion to prevent recurrence.
• d. Both b and c.

Answer: d. Both b and c.

34. For a patient with an ileus (paralysis of the bowel) due to fulminant CDI, how can vancomycin be delivered to the colon?

• a. Through a high-dose IV infusion.
• b. Via a rectal enema, in addition to oral/NG administration.
• c. It cannot be delivered to the colon in this case.
• d. Through a transdermal patch.

Answer: b. Via a rectal enema, in addition to oral/NG administration.

35. Asymptomatic colonization with C. difficile is common and does not require treatment.

• a. True
• b. False

Answer: a. True

36. A patient is being discharged after their second CDI recurrence. Which of the following is an appropriate long-term strategy?

• a. A fecal microbiota transplant (FMT).
• b. Prophylactic daily oral vancomycin.
• c. No further treatment is needed.
• d. A course of IV metronidazole.

Answer: a. A fecal microbiota transplant (FMT).

37. Which of the following is NOT a risk factor for CDI recurrence?

• a. Age > 65 years
• b. Severe underlying disease
• c. Use of a non-first-line agent for the initial episode
• d. A history of IBD

Answer: c. Use of a non-first-line agent for the initial episode

38. The primary symptom of a typical C. difficile infection is:

• a. Constipation
• b. Nausea and vomiting
• c. Watery diarrhea
• d. Abdominal bloating

Answer: c. Watery diarrhea

39. Environmental cleaning to kill C. difficile spores requires what type of agent?

• a. A standard alcohol-based cleaner
• b. A quaternary ammonium compound
• c. A sporicidal agent, such as a 10% bleach solution
• d. Soap and water

Answer: c. A sporicidal agent, such as a 10% bleach solution

40. A patient being treated for CDI should be placed on what type of precautions?

• a. Droplet precautions
• b. Airborne precautions
• c. Contact precautions
• d. No special precautions are needed.

Answer: c. Contact precautions

41. The duration of therapy for an initial episode of CDI with vancomycin or fidaxomicin is:

• a. 5 days
• b. 7 days
• c. 10 days
• d. 14 days

Answer: c. 10 days

42. Which diagnostic test for CDI is highly sensitive but cannot distinguish between active infection and colonization?

• a. Toxin A/B Enzyme Immunoassay (EIA)
• b. Glutamate Dehydrogenase (GDH) assay
• c. Nucleic Acid Amplification Test (NAAT)
• d. Stool culture

Answer: c. Nucleic Acid Amplification Test (NAAT)

43. A multi-step algorithm involving a GDH screen followed by a toxin assay is recommended for diagnosing CDI to improve:

• a. Cost-effectiveness
• b. Turnaround time
• c. Specificity and overall accuracy
• d. Ease of sample collection

Answer: c. Specificity and overall accuracy

44. What is the most important counseling point for a patient discharged on a vancomycin taper?

• a. The tablets can be split in half.
• b. The importance of adhering to the complex, de-escalating schedule.
• c. The medication should be taken with milk.
• d. The taper can be stopped at any time if they feel better.

Answer: b. The importance of adhering to the complex, de-escalating schedule.

45. All patients with diarrhea in the hospital should be tested for C. difficile.

• a. True
• b. False

Answer: b. False

46. A patient with severe CDI has a WBC of 20,000 and an SCr of 2.0 mg/dL. The recommended treatment is:

• a. Oral Metronidazole 500 mg TID
• b. Oral Vancomycin 125 mg QID
• c. Oral Fidaxomicin 200 mg BID
• d. Both b and c are recommended first-line options.

Answer: d. Both b and c are recommended first-line options.

47. A key part of managing CDI is:

• a. Encouraging the use of broad-spectrum antibiotics.
• b. Limiting infection control measures.
• c. Re-evaluating the need for concurrent medications that are risk factors, like PPIs.
• d. Using anti-motility agents to control symptoms.

Answer: c. Re-evaluating the need for concurrent medications that are risk factors, like PPIs.

48. An active learning session covering C. Diff is part of the Patient Care 4 course.

• a. True
• b. False

Answer: a. True

49. Why has metronidazole fallen out of favor for all but the most specific indications in CDI?

• a. It is no longer manufactured.
• b. Clinical trials have consistently shown it to be inferior to oral vancomycin and fidaxomicin.
• c. It has severe cardiovascular side effects.
• d. It is only available as an IV formulation.

Answer: b. Clinical trials have consistently shown it to be inferior to oral vancomycin and fidaxomicin.

50. The ultimate goal of CDI management is to:

• a. Achieve clinical cure of the current episode.
• b. Prevent recurrence of the infection.
• c. Minimize transmission to other patients.
• d. All of the above.

Answer: d. All of the above.