PathoFinala

  1. What are the characteristics of Clostridium?
    • Gram-positive 
    • Obligate anaerobe
    • spore-former (produces 2 toxins[A-enterotoxin & B-A-B cytotoxin])
    • SUPERBUG (problems in hospitals)

  2. What is a characteristic of Clostridium?
    Gram (+)
  3. What is a characteristic of Clostridium?
    Obligate anaerobe
  4. What is a characteristic of Clostridium?
    • spore former
    • produces 2 toxins 
    • -A-enterotoxin
    • -B-A-B cytotoxin
  5. What is a characteristic of Clostridium?
    it's a SUPERBUG that's a problem in hospitals
  6. Where was Clostridium difficile first isolated from?
    infant stool
  7. What was Clostridium difficile first discovered to cause?
    pseudomembranous colitis (PMC)
  8. What is the Clostridium Difficile process?
    1. C. diff vegetative cells and spore are ingested. vegetative cells are killed by stomach acid but spores survive. 

    2. Spores germinate in small bowel upon exposure to bile acids.

    3. Movement to colon by flagella and polysaccharide capsule protects against phagocytosis

    4. Organism multiply in colon and adhere to epithelial cells. 

    • local production of toxins A and B.
    • production of α-TNF, inflammation, increased vascular permeability, neutrophile and monocyte recruitment.

    5. Opening of epithelial cell junctions and cell apoptosis 

    • 6. Local production of hydrolytic enzymes 
    • -connective tissue degradation 

    7. Colitis, pseudomembrane function (dead tissue, fibrin, mucus phagocytes, DNA) and watery diarrhea.
  9. How is C. difficile-Associated Disease (CDAD) transmitted?
    -person to person --> fecal/oral route
  10. What does Clostridium difficile cause?
    inflammatory diarrhea which lead to blood in the diarrhea called dysentery.
  11. What is toxic megacolon?
    complication of inflammatory bowel disease  including c. diff infections
  12. What are the 2 largest single molecule toxins known?
    toxins A and B
  13. What do toxins A and B do?
    modify membrane G proteins that controls may cellular activities 

    -unlike many toxins these types were difficult to work on (tended to aggregate, eluded purification) until genes cloned and characterized tcdA and tcdB.
  14. What do toxins A and B do?
    -activates enteric neurons motility of intestinal contents thus contributing to diarrhea.

    -attract/activates PMNs by cytokines -inflammatory response-mucosal cell destruction

    -effects motility of intestinal contents, leakage of water into lumen-diarrhea.
  15. What is Toxin B cytotoxic for?
    for tissue culture cells. 

    • collapses actin cytoskeleton, shape of cells lost. 
    • damages underlying tissue of the mucosal membrane and intestinal wall.
Author
mnvang321
ID
312801
Card Set
PathoFinala
Description
11-13
Updated