Clostridium difficile Infections

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.
• 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.

Learn about Clostridium difficile, a bacterium causing pseudomembranous colitis, and its pathogenesis, risk factors, and epidemiology.