Clostridium difficile Flashcards
What type of bacteria is C. difficile?
Gram-positive bacillus (rod)
Why is C. difficile hard to eradicate from the environment?
forms endospores - stability and persistence
Describe 2 types of exotoxins produced by C. difficile.
Both are glucosyltransferases that glycosylate and inactivate Rho-family GTP-binding proteins:
- Enterotoxin A - causes excessive fluid secretion (diarrhoea), inflammatory response and has some cytopathic effect
- Cytotoxin B - disrupts protein synthesis, cytoskeleton disorganisation
How is C. difficile transmitted?
contamination of environment with spores
Is C. difficile part of the normal human flora?
Yes, minor component of large intestine flora
When does C. difficile become pathogenic?
proliferates when predominant species in large intestine community are suppressed by (virtually all) antimicrobial drugs
What type of disease does C. difficile cause?
varies from:
- diarrhoea
- pseudomembranous colitis - pseudomembranous exudate (composed of mucus, fibrin, inflammatory cells and cell debris overlying an ulcerated epithelium)
How is C. difficile infection diagnosed?
- cultured from stool sample and identified by routine anaerobic procedures (anaerobic on blood agar)
- ELISA for exotoxins A and B (more rapid)
- PCR
Describe the supportive management of C. difficile infection.
- Stop: antibiotics, proton pump inhibitors, immunosuppressant therapy/steroids, laxatives and prokinetics, opioids
- Fluid replacement
Describe the specific management of C. difficile infection.
Antibiotics:
- not severe (or enteral route not available) = METRONIDAZOLE
- severe = VANCOMYCIN (can only be given orally)
What type of antibiotic is vancomycin and what is its MOA?
glycopeptide - binds cell wall amino acids, preventing peptidoglycan chain elongation
Which clostridium species cause tetanus and botulism?
C. tetani
C. botulinum
Name an antibiotic type that particularly increases risk of C. difficile infection.
cephalosporins
