Escherichia coli (E. coli) O157:H7 or Hamburger Disease

Escherichia coli (E. coli) O157:H7, sometimes called Hamburger Disease, is a cause of foodborne illness. Infection often leads to bloody diarrhea, and occasionally to kidney failure. Most illness has been associated with eating undercooked, contaminated ground beef. Person-to-person contact in families and child-care centres is also an important mode of transmission. Infection can also occur after drinking unpasteurized milk or other manure-contaminated foods that are not cooked and after swimming in or drinking sewage-contaminated water.

You can prevent E. coli O157:H7 infection by thoroughly cooking ground beef, avoiding unpasteurized milk, and washing your hands carefully.

What is E. coli O157:H7?

  • E. coli O157:H7 is one of hundreds of strains of the bacterium Escherichia coli. Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.
  • Many people get sick from E. coli O157:H7 by eating food and drinking beverages that contain the harmful bacteria. Once the bacteria enter your body, they attach to the cells lining your intestinal walls and begin to multiply. As the bacteria grow in numbers, they release powerful toxins that can severely damage the lining of your intestine, causing cramping and diarrhea.
  • In most cases E. coli food poisoning comes from products that may carry the bacteria including:
    • undercooked ground beef, hamburgers
    • unpasteurized milk and apple cider
    • ham, turkey, roast beef
    • sandwich meats
    • raw fruits and vegetables
    • cheese and
    • untreated water

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How is E. coli O157:H7 spread?

  • E.coli 0157:H7 bacteria infect the intestine of cattle. When animals are slaughtered the bacteria contaminate the outer surface of the meat. The bacteria are further mixed into the meat during the grinding process. This is why it is sometimes called “hamburger disease”.
  • E.coli 0157:H7 infections can be spread by many food sources such as undercooked ground beef, unpasteurized milk and apple cider, ham, turkey, roast beef, sandwich meats, raw fruit and vegetables, cheese and untreated water. Once someone has eaten contaminated food, this infection can be passed from person-to-person, by hand-to-mouth contact (fecal-oral route).
  • This is particularly likely among toddlers who are not toilet trained. Family members and playmates of these children are at high risk of becoming infected. In fact, bacteria can be present in the stools of young children one to two weeks after their symptoms have gone away. Older children rarely carry the organism without symptoms. 
  • Note: If you work as a food handler, or in a child-care (babysitting) or health care setting and suspect you may have food poisoning, you should not got to work until after you have visited your doctor and had two negative stool samples.

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What are the symptoms?

  • Some people who become infected with E. coli 0157:H7 do not get sick at all.  
  • Most commonly, people develop stomach cramps, and diarrhea within 2 to 8 days of eating food contaminated with E. coli 0157:H7. Some people may have bloody diarrhea.
  • About 5-10% of people who become infected with E. coli 0157:H7 develop Hemolytic Uremic Syndrome (HUS). Most of these are children and the elderly. Some people with HUS may need blood transfusions and kidney dialysis. Most people with HUS get better. However, it is occasionally fatal. Others live with side effects like permanent kidney damage.

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How is E. coli O157:H7 infection diagnosed?

  • Infection with E. coli O157:H7 is diagnosed by detecting the bacterium in the stool.

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How is the illness treated?

  • Most people recover in 5-10 days. There is no evidence that antibiotics improve the course of disease and, in fact, treatment with antibiotics may precipitate kidney complications. Anti-diarrheal agents, should also be avoided.
  • Hemolytic uremic syndrome is a life-threatening condition usually treated in an intensive care unit. Blood transfusions and kidney dialysis are often required. With intensive care, the death rate for Hemolytic Uremic Syndrome is three to five percent.

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What are the possible long-term consequences of infection?

  • Persons who only have diarrhea usually recover completely.
  • About one-third of persons with Hemolytic Uremic Syndrome have abnormal kidney function many years later, and a few require long-term dialysis.

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What can be done to prevent the infection?

  • E. coli O157:H7 will continue to be an important public health concern as long as it contaminates meat. Preventive measures may reduce the number of cattle that carry it and the contamination of meat during slaughter and grinding. Research into such prevention measures is just beginning.

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What can you do to prevent E. coli O157:H7 infection?

  • Make sure that persons with diarrhea, especially children, wash their hands carefully with soap after bowel movements to reduce the risk of spreading infection, and that persons wash their hands after changing soiled diapers. Anyone with a diarrheal illness should avoid swimming in public pools or lakes, sharing baths with others, and preparing food for others.
  • Cook all ground beef and hamburger thoroughly. Because ground beef can turn brown before disease-causing bacteria are killed, use a digital instant-read meat thermometer to ensure thorough cooking. Ground beef should be cooked until a thermometer inserted into several parts of the patty, including the thickest part, reads at least 71º C (160º F). Persons who cook ground beef without using a thermometer can decrease their risk of illness by not eating ground beef patties that are still pink in the middle.
  • If you are served an undercooked hamburger or other ground beef product in a restaurant, send it back for further cooking. You may want to ask for a new bun and a clean plate, too.
  • Avoid spreading harmful bacteria in your kitchen. Keep raw meat separate from ready-to-eat foods. Wash your hands, counters, and utensils with hot soapy water after they touch raw meat. Never place cooked hamburgers or ground beef on the unwashed plate that held raw patties. Wash meat thermometers in between tests of patties that require further cooking.
  • Drink only pasteurized milk, juice, or cider. Commercial juice with an extended shelf-life that is sold at room temperature (e.g. juice in cardboard boxes, vacuum sealed juice in glass containers) has been pasteurized, although this is generally not indicated on the label. Juice concentrates are also heated sufficiently to kill pathogens.
  • Wash fruits and vegetables thoroughly, especially those that will not be cooked. Children under 5 years of age, immunocompromised persons, and the elderly should avoid eating alfalfa sprouts until their safety can be assured. Methods to decontaminate alfalfa seeds and sprouts are being investigated.
  • Drink municipal water that has been treated with chlorine or other effective disinfectants.
  • Avoid swallowing lake or pool water while swimming.  

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References

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