Shigella

  1. Organism
    • Four species
    • Shigella dysenteriae=most disease, no flagella
  2. Epidemiology
    • Strictly human disease
    • Common infectious diarrhea
    • Fecal-oral
    • Low infecting dose (<200)
    • S. dysentariae type 1 causes most severe disease
  3. Pathogenesis
    • Acid resistant
    • Invasion of colonic mucosa
    • Adheres to M cells, translocates to phagocytic cells
    • Cause apoptosis in macrophages/M cells
    • Apoptosis leads to viral release -> incasin protein Ag -> unique actions
    • Create actin tail by contoling polymerization of actin fibriles
    • Cell to cell spread
    • Focal ulcers in mucosa -> inflammatory diarrhea
    • Stx -> increases morbidity
  4. Manifestations
    • Acute inflammatory colitis and bloody diarrhea
    • Triad: cramps, painful straining, frequent, small volume bloody mucoid discharge
    • Diagnosis: Selective media
    • Tx: usually self-limiting, high resistance to ampicillin
Author
ehamm
ID
117598
Card Set
Shigella
Description
Shigella
Updated