Enterohemorrhagic E. coli

Aka: Enterohemorrhagic E. coli, EHEC, E. coli 0157, Shiga Toxin-producing E. coli, STEC

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II. Pathophysiology

  1. Enterohemorrhagic E. coli (EHEC) causes bloody Diarrhea
  2. More than 60% of E. coli EHEC strains release Shiga-like toxin (e.g. 0157:H7, 0104:H4)

III. Causes: Foodborne Illness (Shiga-toxin producing E. coli)

  1. Meat products
    1. Bovine (Most common)
      1. Undercooked hamburger (often commercial source)
    2. Pork
    3. Poultry
    4. Lamb
  2. Mayonnaise
  3. Sausage
  4. Salami
  5. Raw milk
  6. Alfalfa sprouts
  7. Unpasteurized apple cider and apple juice

IV. Symptoms

  1. Rapid onset in 12-72 hours
  2. Enterohemorrhagic E. coli (EHEC) causes an acute hemorrhagic colitis

V. Signs

  1. Bloody Diarrhea in 95%

VI. Complications: Shiga-toxin producing EHEC Strains

  1. Hemolytic Uremic Syndrome (HUS)
  2. Thrombotic Thrombocytopenic Purpura (TTP)

VII. Labs

  1. See Hemolytic Uremic Syndrome (HUS)
  2. Complete Blood Count
    1. White Blood Cell Count is variably increased in EHEC
    2. Hemoglobin may be decreased to <9 mg/dl in HUS
    3. Platelet Count may be decreased to <150,000 in HUS
  3. Metabolic panel
    1. Electrolyte abnormalities (related to severe Diarrhea)
      1. Hyponatremia
      2. Hypokalemia
    2. Serum Creatinine and Blood Urea Nitrogen
      1. Increased in Dehydration as well as HUS
  4. Urinalysis
    1. Microscopic Hematuria and Proteinuria with HUS
  5. Shiga-Toxin Producing E. coli Diagnosis
    1. Specific E.Coli 0157:H7 Culture
    2. Shiga-Toxin ELISA Assay
    3. Shiga-Toxin 1 and 2 DNA PCR

VIII. Management

  1. See Acute Diarrhea
    1. Includes general measures including hydration
  2. Avoid antidiarrheal agents such as Loperamide (Imodium)
  3. Avoid Antibiotics in most cases (esp. under age 10 years old)
    1. Antibiotics increase risk of Hemolytic Uremic Syndrome (to as much as 25% Incidence)
      1. Wong (2012) Clin Infect Dis 55(1): 33-41 +PMID:22431799 [PubMed]
    2. In some STEC epidemics, Antibiotics have been used with decreased adverse outcomes
      1. If used, Azithromycin appears least likely to cause HUS
      2. Nitschke (2012) JAMA 307(10): 1046-52 +PMID:22416100 [PubMed]

IX. Resources

  1. CDC E. coli outbreaks (primarily 0157:H7)
    1. http://www.cdc.gov/ecoli/outbreaks.html
  2. WHO Enterohemorrhagic E. coli
    1. http://www.who.int/mediacentre/factsheets/fs125/en/

X. References

  1. (2015) Sanford Guide to Antimicrobials, accessed IOS app 5/7/2016
  2. Bower (1999) Pediatr Infect Dis J 18:909-10 [PubMed]
  3. Page (2013) Med Clin North Am 97(4):681-95 +PMID:23809720 [PubMed]

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