ID

Shigella

search

Shigella, Bacillary Dysentery, Shigellosis

  • Epidemiology
  1. Most common cause of bloody Diarrhea in the United States (since 2010 when surpassed E. coli 0157:H7)
  2. Only small inoculum required for infection
  3. Transmission
    1. Human feces
    2. Hand contact
    3. Fly infestation
  • Causes
  • Foodborne Sources
  1. Contaminated drinking water
  2. Contaminated raw produce
  3. Foods contaminated by infected food handler
  • Pathophysiology
  1. Invades bowel mucosa
  2. Produces enterotoxin in colon
  • Symptoms
  1. Onset: 4 to 7 days (as early as 1-3 days in some cases)
  2. Duration: 24 to 48 hours
  3. Diarrhea (often severe)
  4. Tenesmus
  5. Abdominal cramps
  6. Nausea and Vomiting
  7. Lassitude
  8. Bloody stool (51% of cases)
  9. Stool mucus may be seen
  • Signs
  1. Fever (58% of cases)
  2. Dehydration
  3. Lower abdominal tenderness
  1. Hyperemic bowel wall
  2. Mural edema
  3. Purulent exudate
  • Labs
  1. Stool microscopy
    1. Stool Mucus
    2. Fecal Leukocytes present
  2. Complete Blood Count
    1. Leukocytosis or Leukopenia
  3. Routine Stool Culture
    1. Negative only after 48 hours of antibiotics
  • Management
  1. See Acute Diarrhea
  2. Treat immunocompromised patients for 7-10 days
  3. Trimethoprim-Sulfamethoxazole (Bactrim) is no longer recommended due to Antibiotic Resistance
  4. Adults with dysentery: first-line agents
    1. Ciprofloxacin 500 mg orally twice daily for 3 days or
    2. Levofloxacin 500-750 mg orally daily for 3 days
  5. Adults with dysentery: alternative agents
    1. Azithromycin 500 mg daily for 3 days or
    2. Ceftriaxone 1-2 g IV daily for 3 days (in severe disease)
  6. Children with dysentery: first-line agents
    1. Azithromycin 10 mg/kg/day daily for 3 days or
    2. Ceftriaxone 50-75 mg/kg/day for 2- 5 days (in severe disease)
  7. References
    1. (2015) Sanford Guide to Antimicrobial Therapy, IOS app accessed 5/8/2016
  • Resources