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E. coli Infection

 

Definition

Hamburger disease is an intestinal infection caused by a disease-causing (pathogenic) strain of Escherichia coli (E. coli), a bacterium that inhabits our gut. Most E. coli bacteria are harmless, and may be used as indicators of pollution in drinking water samples. However, one of the most common pathogenic strains, E. coli O157:H7 (also referred to as enterohemorrhagic E. coli [EHEC], Shiga toxin-producing E. coli [STEC] and verotoxigenic E. coli [VTEC]), causes mild to severe diarrhea, and can result in serious side effects or death. There are many pathogenic strains of E. coli, but the one referred to here is E. coli O157:H7.  

Symptoms

  • E. coli infection may cause mild to severe symptoms including watery diarrhea and stomach cramps. In severe cases, diarrhea may become bloody.
  • Fever is rare.
  • Symptoms start an average of 3 to 4 days (range: 2 to 10 days) after exposure to the bacteria, and usually last between 5 to 10 days.
 

Causes

  • Pathogenic, toxin-producing E. coli bacteria can infect the intestinal tract when food we eat or water we drink is contaminated with them.  E. coli O157:H7 is the most well known of the verotoxin producing E. coli. In the past, this infection has been referred to as ‘hamburger disease’.
  • Toxin-producing E. coli is one of the more severe causes of bacterial diarrhea in North America.
  • Between 2007-2011, an average of 136  infections were reported per year to the B.C. Centre for Disease Control.
  • The bacteria that produce these toxins (or poisons) are found in the stomach and manure of cattle, and sometimes that of sheep, goats and deer. When animals are butchered, sometimes the gut is nicked by the knife, contaminating the carcass.
  • Human infection is usually due to eating undercooked hamburger or foods contaminated with raw or undercooked meat juices. Other manure-contaminated foods that are not cooked have also caused infection.
  • Some foods are considered to carry such a high risk of infection with E. coli O157:H7 or other pathogens health officials recommend that people avoid them completely. These foods include unpasteurized (raw) milk and unpasteurized apple cider.
  • Contaminated drinking water has also caused infections, as well as swimming in contaminated water (e.g. recreational water that drains cattle pastures).
 

Complications

  • Approximately 15% of children, and a smaller percentage of adults who are diagnosed with STEC infection develop a potentially life-threatening complication known as hemolytic uremic syndrome (HUS).
  • Clues that a person is developing HUS include decreased frequency of urination, feeling very tired, and losing pink color in cheeks and inside the lower eyelids. Persons with HUS should be hospitalized because their kidneys may stop working and they may develop other serious problems. Although many persons with HUS recover within a few weeks, about 50% need dialysis and some suffer permanent damage or die (about 5%).
  • Although pathogenic E. coli are usually gone from the feces by the time symptoms disappear, they can go on being excreted in stools for weeks or months. Careful hand washing is important to prevent the spread of this illness, and people who work in high risk occupations may need to provide stool samples free of the bacteria before returning to work.
 

Tests and Diagnosis

  • Diagnosis is done through culturing of stool samples.
  • If the bacteria are not detectable in the stool, it may be possible to detect verotoxin, an indication that infection caused by E. coli O157:H7 has occurred.
  • To detect outbreaks, "fingerprinting" can be done to determine if all the E. coli detected in samples are of the same strain.
 

Treatment and Drugs

  • Anyone who has bloody diarrhea should see their doctor.
  • Drinking lots of clear fluids is important.
  • If you or your child have symptoms of infection, it is important to see a doctor. This is especially important if someone has bloody diarrhea. Your doctor may ask for a stool sample to test for E. coli O157:H7 and will determine if treatment is necessary.
  • Non-specific supportive therapy, including hydration, is important.
  • Antibiotics and anti-diarrheal drugs should not be used to treat this infection, unless your doctor prescribes them, since taking antibiotics may increase the risk of HUS.
 

Coping and Support

  • If you think you have an E. coli infection, see your family doctor for testing, advice and treatment. E. coli is passed in the feces; therefore, people with diarrhea that may be due to an infectious illness should not go to work or school.
  • If an infected person is a food handler, health care worker or works in or attends a day care, it is possible for them to transmit E. coli to others in these settings. A public health official will contact them or their parents/guardians to discuss when they can return to work or day care (basically when two stool samples are clear). See the guideline on Exclusion of Enteric Cases and their Contacts from High Risk Settings.

Prevention

 
  • Peel any fruits or vegetables to be eaten raw, or wash them well in plenty of clean water.
  • Ground meat and rolled roasts (e.g. beef roulade) are particularly hazardous, compared to whole pieces of meat like steaks and whole roasts. This is because the bacteria which get onto the surfaces of the meat during the butchering process get mixed right through the meat when it is ground up. Bacteria on the surface of whole cuts used in beef roulade are covered by other cuts which are rolled and tied together. Beef roulade and ground meats must be cooked to well done.
  • Use separate cutting boards for raw and ready-to-eat foods.
  • When you take raw meats out to your barbecue, get a fresh, clean plate for the cooked meat.
  • Do not use marinade as a sauce for cooked meat.
  • Avoid unpasteurized milk and unpasteurized juices.
  • If a trip to a petting zoo or farm is planned, see the Enteric and Zoonotic Disease Prevention at Petting Zoos and Open Farms information in the Communicable Disease Control Maunal for information on the risks associated with animal contact and what you can do to protect yourself and your children from infection.

WASH YOUR HANDS:

  • Before eating
  • Before preparing food
  • Immediately after handling raw meat or poultry, and before touching anything else
  • After using the toilet or changing diapers
  • After touching animals
  • Make sure children, particularly those who handle pets or feed them raw pet treats, wash their hands carefully immediately afterwards, especially if they suck their thumbs or put their hands into their mouths.  Wash their hands for them if they are too young.

 

  • If your local drinking water provider has issued a Boil Water Notice for your community, take the advice seriously.
  • Do not drink untreated surface water from a spring, stream, river, lake, pond or shallow well. Assume it is contaminated with animal feces.
  • Boil or disinfect water from these sources if it is used for drinking, making ice cubes, washing uncooked fruits and vegetables, making baby formula, brushing teeth, and rinsing dentures or contact lenses.
  • Boil for at least 1 minute at a rolling boil. At elevations above 2000 m (6562 ft) boil for at least 2 minutes, or
  • Disinfect water if it is not cloudy using 1 drop of bleach per litre of water. Shake and allow to stand for 30 minutes before drinking. For more information, go to How To Disinfect Drinking Water - BC HealthFile #49b.

 

Last Updated: October 3, 2012