Review Question - QID 101466

This patient is presenting with pseudomembranous colitis caused by Clostridium difficile. C. difficile produces 2 toxins: Toxin A, enterotoxin, binds to the brush border of the gut while Toxin B, cytotoxin, destroys the cytoskeletal structure of enterocytes. The preferred initial treatment is oral fidaxomicin.

Clostridium difficile is a Gram-positive, spore-forming, obligate anaerobic bacilli that is known to cause infection in the colon in the context of antibiotic use, especially clindamycin and ampicillin. The bacteria is thought to colonize the mucosa of the large intestine due to a disruption of normal flora after antibiotic therapy.

Kuehne et al. report C. difficile is virulent when either toxin A or toxin B are functional. They emphasize the importance of each toxin and the necessity to consider both when developing countermeasures against C. difficile infection.

Scroeder et al. report the major predisposing factors for symptomatic C. difficile colitis include antibiotic therapy; advanced age; multiple, severe underlying diseases; and a faulty immune response to C. difficile toxins. They found that the most common confirmatory study is an enzyme immunoassay for C. difficile toxins A and B.

Illustration A shows friable patches of necrotic tissue along the lining of the colon that is characteristic of pseudomembranous colitis.

Incorrect Answers:
Answer 1: Clindamycin's disruption of normal colonic flora is likely the cause of pseudomembranous colitis and, therefore, would not be an adequate treatment.
Answers 3, 4, & 5: Neither penicillin, tetracycline, or erythromycin are acceptable treatments for pseudomembranous colitis.