While Clostridium difficile (C diff) is a common infection, there is a lot to know.  A thorough but brief review is a good place to test your knowledge (Clin Gastroenterol Hepatol 2012; 10: 581-92).

• a. When was C diff discovered?
• b. When was C diff identified as a cause of antibiotic-associated diarrhea?
• c. What antibiotics have been associated with a surge in severity and frequency of C diff infections?
• d. Which C diff strains are the predominant cause of severe C diff?
• e. How many C diff infections are occurring yearly in hospitalized patients in U.S.?
• f. What are the most important risk factors?
• g. How does the risk profile change for multiple antibiotics?
• h. What time of year sees the greatest number of infections?
• i. What does C diff smell like?
• j. What % of antibiotic-associated diarrhea is due to C diff?
• k. What clinical parameters may indicate severe infection and which ones indicate fulminant infection?
• l. How much does a nucleic acid amplification test (NAAT) cost compare to enzyme immunoassay (EIA)?  How does this test work? What are the advantages/disadvantages?
• m. How to treat severe infection?
• n. What instructions should be given to prevent C diff in hospital?

Answers:

• a. 1935
• b. 1970s
• c. Fluoroquinolones
• d. BI/NAP1/027.  This strain has hypersecretion of toxins A & B, the presence of binary toxin, and resistance to fluoroquinolones.
• e. CDI present in 300,000 hospitalized patients in 2005 (vs. 85,000 in 1993)
• f. Hospitalization, older age (>65 years), and receipt of antibiotics (especially during 1st two months).
• g. Hazard ratio 2.5 for two antibiotics, HR 9.6 for exposure to five antibiotics
• h. Winter
• i. “Horse stable”
• j. 15-25%
• k. Severe: WBC>15,000, Creatinine >1.5 fold patient’s baseline.  Also, albumin <2.5, admission to ICU, pseudomembranes on endoscopy, comorbid diseases.  Fulminant: (50% mortality) colon >6cm in diameter/toxic megacolon, WBC >50,000, lactate >5 mmol/L.
• l. ~10 times the cost.  Works by identifying genes that encode toxins by PCR or loop-mediated amplification of DNA.  Test is very sensitive and rapid but may have false-positives.  Some recommend using a less expensive test for screening to decrease costs.
• m. Vancomycin up to 500mg QID (NG/PO) plus metronidazole.  If complete ileus, vancomycin can be given rectally
• n. Hand hygiene (not alcohol): either soap or chlorhexidine, contact precautions, cleaning environment –chlorine solutions effective (1000-5000 ppm), antimicrobial stewardship (especially reducing clindamycin and fluoroquinolones)

How many did you get right?

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