Antibiotics destroy the normal intestinal bacterial flora that normally suppresses C. difficile overgrowth. C. difficile is resistant to most of the commonly used antibiotics.
High-risk antibiotics (odds ratio ≥ 5)
Clindamycin
Cephalosporins
Fluoroquinolones
Advanced age
Gastric acid suppression (e.g., with proton pump inhibitors) or bypass (e.g., enteral feeding)
Recent hospitalization
Pathophysiology
Toxin A (enterotoxin): binding to brush border of enterocytes → disruption of actin cytoskeleton functioning → increase in epithelial permeability and apoptosis → diarrhea
Toxin B (cytotoxin): same as in toxin A, but can also cause pore formation within the endosomal membrane via insertion of the translocation domain → release of endosomal content into the cytosol → cytopathic effect