Questions and Answers
What is the primary factor that enhances the susceptibility to C.difficile infection?
What type of organism is Clostridium difficile?
Which of the following antibiotics is NOT implicated in hospital outbreaks of C.difficile infection?
What is the mechanism of pathogenesis of Clostridioides difficile?
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Why was Clostridium difficile so named?
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What is the primary mechanism by which toxins A and B disrupt cellular function?
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Which of the following factors has been identified as a risk factor for the development of pseudomembranous colitis?
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Which group of individuals is most likely to develop symptomatic infection due to toxin A?
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Why do infants generally not develop symptomatic infections due to difficile?
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What distinguishes the hypervirulent epidemic strain BI/NAP1/027 from other strains?
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Study Notes
Clostridium difficile Overview
- Clostridium difficile is an obligate anaerobic, gram-positive, spore-forming bacillus.
- Known for causing pseudomembranous colitis, a colonic disease associated with prolonged antimicrobial use.
- Recently reclassified into a separate genus, Clostridioides difficile.
Pathogenesis
- A significant cause of healthcare-associated infections, particularly common in the Western world.
- In India, cases are reported less frequently.
Risk Factors
- Prolonged Hospital Stay: Spores are abundant in nature and can colonize the colon of hospitalized patients.
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Prolonged Antimicrobial Use: Disruption of normal colonic flora increases susceptibility to infection.
- Cephalosporins, such as ceftriaxone, frequently implicated.
- Other antibiotics like clindamycin, ampicillin, and fluoroquinolones also linked to outbreaks.
- All antibiotics, including vancomycin and metronidazole, can risk infection with extended use.
Mechanism of Disease
- Pathogenesis is toxin-mediated; toxigenic strains are responsible for disease.
- Produces two potent exotoxins:
- Toxin A (enterotoxin)
- Toxin B (cytotoxin)
- Both toxins disrupt the actin cytoskeleton of epithelial cells, leading to diarrhea and pseudomembrane formation.
- Asymptomatic colonization can occur in infants, who lack necessary mucosal toxin receptors.
Host Immune Response
- Strong IgG response to toxin A often leads to asymptomatic carriage.
- Inadequate IgG response may result in symptomatic disease.
Additional Risk Factors
- Suppressed normal flora increases risk, as normal flora helps to resist spore germination.
- Advanced age (>65 years) increases vulnerability.
- Conditions such as immunosuppression, cancer chemotherapy, and recent gastrointestinal surgeries heighten risk.
- Use of gastric acid suppressant medications contributes to risk.
- Utilization of electronic rectal thermometers also noted as a risk factor.
Hypervirulent Strain
- A ribotype BI/NAP1/027 has been identified as a hypervirulent strain, producing elevated toxin levels.
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Description
Learn about Clostridium difficile, a bacterium causing pseudomembranous colitis, and its pathogenesis, risk factors, and epidemiology.
