All About E. Coli

Symptoms, Treatment and Prevention

E. coli magnified x7000. PASIEKA/Science Photo Library/Getty Images

What Is E. Coli?

Escherichia coli (E. coli) are a group of bacteria that can cause a variety of illnesses in humans, including diarrhea, urinary tract infections, respiratory illnesses pneumonia and other problems. There are also many types of E. coli bacteria that are harmless.

One type of E. coli that often causes illness and outbreaks in humans is known as E. Coli O157. There are other strains that cause illness as well, but O157 is the most notorious, so we will focus on that strain here.

How Do You Get E. Coli O157?

E. coli lives in the intestinal tracts of humans and animals, such as cattle, goats, elk, sheep and deer. Other animals, including pigs and birds, can pick it up from the environment and spread it. The most common source of E. coli infection in humans is cattle.

E. coli is spread through contaminated fecal matter from animals that are carrying the disease (these animals are typically not sick themselves) or from people who have an infection but do not wash their hands properly after using the bathroom. These microscopic amounts of fecal matter end up on food that we eat and then cause infections. It's gross, but reality. 

Other sources of E. coli include raw (unpasteurized) milk, water that has not been disinfected, unpasteurized apple cider, soft cheese made from unpasteurized milk, swallowing lake water while swimming and touching animals in petting zoos or animal exhibits.


Symptoms of an intestinal E. coli infection vary but can include:

  • Stomach cramps
  • Diarrhea (usually bloody)
  • Vomiting
  • Low-grade fever (typically not over 101)

These symptoms usually resolve on their own within 5 to 7 days. E. coli infections are mild for most people, but they can be serious or even life-threatening in others.

Symptoms of an infection typically start 3 to 5 days after exposure to the bacteria, but they can occur as early as one day or as late as 10 days after exposure.

Are There Any Complications?

One of the most serious complications is called "hemolytic uremic syndrome" (HUS). Between 5 to 10% of people with E. coli infections suffer from this complication that can result in kidney failure or even death. Symptoms of HUS include:

  • Decreased frequency of urination
  • Fatigue
  • Losing color in cheeks and inside lower eyelids

How Is E. Coli Treated?

For a typical infection, treatment mostly consists of staying hydrated. Drinking water or electrolyte drinks, such as Gatorade or Pedialyte (for children), will help to prevent dehydration. Eating when you have a stomach bug is not that important as long as you are staying hydrated. For those people who are unable to keep any liquids down, IV fluids may be needed.

Antibiotics are not effective against E. coli and should not be used because they may increase the risk of complications, such as HUS. Antidiarrheal medications, such as Immodium, should be avoided, because they can also increase this risk.

People who develop HUS should be hospitalized to manage the illness.

Various treatments may be needed depending on the symptoms.

How Can E. Coli Infections be Prevented?

Nearly everyone is at risk for getting an E. Coli infection. Although infants, young children, older adults and people with compromised immune systems are at the highest risk for serious illness, even healthy adults can have complications. Some things you can do to minimize your risk of infection include:

  • Good hand washing. Especially after using the restroom, changing diapers and before preparing or eating food. Also, wash your hands thoroughly after touching any animals or their environments, even your own pets.
  • Cook meats thoroughly. Ground beef and meat that has been needle-tenderized should be cooked to an internal temperature of at least 160 degrees F.
  • Avoid raw or unpasteurized milk, cheeses or other dairy products and unpasteurized fruit juices or ciders.
  • Avoid swallowing water when swimming anywhere.
  • Be sure to wash cooking surfaces, such as cutting boards, and utensils thoroughly with hot water and soap after cutting or preparing raw meat.


”Escherichia Coli.” Division of Foodborne, Bacterial and Mycotic Diseases (DFBMD) 27 Mar 08. Centers for Disease Control and Prevention. 17 June 08.

”Foodborne Illness.” Division of Foodborne, Bacterial and Mycotic Diseases 25 Oct 05. Centers for Disease Control and Prevention. 20 June 08.

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