Escherichia coli Infection

(E. coli Infection, Escherichia coli O157:H7, Shiga Toxin)


Escherichia coli (E. coli) infection is from a bacterium. It leads to inflamed bowels. The illness ranges from mild to life-threatening.


There are different types of E.coli bacteria. A certain type causes bowel infection. It comes from contact with the stools of infected people and animals. The bacteria enters the mouth and passes to the digestive tract. This can happen from:

  • Eating contaminated foods, especially:
    • Undercooked ground beef
    • Processed meats
    • Raw foods
  • Drinking contaminated water
  • Drinking unpasteurized milk
  • Touching a contaminated animal or object

Digestive Pathway Through Stomach and Intestines

Digestive pathway
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Risk Factors

E. coli infections are more common in children under 5 years old.

Other things that raise the risk are:

  • Close contact a person infected with E. coli
  • Being at the site of a food-related outbreak, such as:
    • A hotel or cruise ship
    • Restaurant or catered event
  • Contact with animals


Symptoms of E. coli infection include:

  • Diarrhea that turns bloody
  • Severe belly cramps
  • Fever
  • Thirst
  • Passing only small amounts of urine
  • Feeling tired and weak
  • Nausea or vomiting


The doctor will ask about your symptoms and health history. A physical exam will be done. A sample of stool may be tested. It will confirm the diagnosis.

If symptoms are severe, blood and urine tests may be done.


Most people get better in 5 to 10 days. Treatment may include fluids by mouth or IV. Severe infections or other problems may need further care.


To reduce the risk of an E. coli infection:

  • Follow proper guidelines for:
    • Handwashing
    • Food safety


Centers for Disease Control and Prevention
National Institute of Allergy and Infectious Diseases


Canadian Food Inspection Agency
Public Health Agency of Canada


E. coli infection. Family Doctor—American Academy of Family Physicians website. Available at: Accessed March 31, 2021.
E. coli (Escherichia coli). Centers for Disease Control and Prevention website. Available at: Accessed March 31, 2021.
Enterohemorrhagic escherichia coli (EHEC) infection. . EBSCO DynaMed website. Available at: Accessed March 31, 2021.
Yang SC, Lin CH, et al. Current pathogenic Escherichia coli foodborne outbreak cases and therapy development. Arch Microbiol. 2017;199(6):811-825.
Last reviewed December 2020 by EBSCO Medical Review Board David L. Horn, MD, FACP
Last Updated: 3/31/2021

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