Clostridium difficile Microbiology

  1. Gram stain and shape of C diff?
    Gr + Rod
  2. What is C diff’s oxygen metabolism?
    Obligate anaerobe
  3. True/false: C diff are non-endospore formers
    False; they make maaaaad endospore that can survive to up to 2 years
  4. True/false: Clostridium are gram-positive nonfilamentous spore-froming rods like Bacillus
  5. Clostridium ____ (can/cannot) grow in aerobic condition. Bacillus _____ (can/cannot) grow in aerobic condition
    • Clostridium cannot (they are obligate anaerboes)
    • Bacillus can grow in aerobic condition
  6. Which Clostridium species can cause pseudomembranous colitis? Which can cause gas gangrene?
    • Colitis – C diff
    • Gas gangrene- C perfringens
  7. True/false: C diff is found ubiquitously, in soil, water, lower GI of humans, animals
  8. What are the clinically important anaerobes?
    • Clostridium (Gram + nonfilamentous rods)
    • Bacteroides (Gram negative rods)
    • Actinomyces (Gr + filamentous rods)
    • (Think: Can’t Breathe Air)
  9. What are virulence factors for C difficle?
    • Endospores
    • Flagella
    • Toxins A and B
  10. What is Toxin A?
    • Enterotoxin
    • Directly activate neutorphil
  11. What is Toxin B?
    • Cytotoxin
    • Causes actin depolymerization and eventual cell death
  12. Which toxin directly activates neutrophils?
    Toxin A (enterotoxin)
  13. Which toxin is the more potent toxin that can mediate colonic mucosal damage?
    Toxin B (cyototoxin)
  14. True/false: C diff can have strain that does not have either toxin, or could have just one toxin
  15. True/false: C diff toxin have little effect to the body until C diff becomes the predominant organism and toxin level is high enough
  16. What is the greatest risk facto for C diff?
    Antibiotic use
  17. Is C diff associated diarrhea transmitted endogenously or exogenously.
    BOTH! Either overgrowth of C diff (endogenous) or fecal-oral route (exogenous) transmission
  18. CDAD presents with which symptoms?
    • Foul smelling watery diarrhea (because anaerobes)
    • Psuedomembranous colitis
  19. What is the most common method of diagnosing CDAD?
    • **PCR of stool – very sensitive and specific!
    • ELISA of stool for toxins A/B (not for endospores)
    • Glutamate dehydrogenase immunoassays (can’t tell if the organism is MAKING toxin or has GENES for toxin)
  20. Which diagnostic method of CDAD gives false positive?
    GDH immunoassays (glutamate dehydrogenase)
  21. Best hand hygiene to prevent CDAD?
  22. What is fecal transplant?
    Someone else’s poop in you. Administered via enema, colonoscope, NG/jeujunal tube or oral pill
  23. Treatment for CDAD?
    • Discontinue antibiotic
    • Fluid replacement
    • Oral vanco or oral fidaxomicin
  24. How do psuedomembranes appear on sigmoidoscopic exam?
    Raised yellow or off-white plaques up to 2 cm diameter scatter on colorectal mucosa
Card Set
Clostridium difficile Microbiology
GI Final- Microbiology