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bacterial endotoxin|bloody diarrhea|enterohemorrhagic infection|Escherichia coli|food-borne illness|gastroenteritis

E. coli Infection

Last Updated September 2023 | This article was created by editorial staff and reviewed by Kyle Bradford Jones, MD, FAAFP

What is E. coli?

E. coli is short for Escherichia coli—bacteria (germs) that are found on food and in the environment. E. coli cause severe cramps and diarrhea. These bacteria are a leading cause of bloody diarrhea. The symptoms are worse in children and older people, and especially in people who have another illness. E. coli infection is more common during the summer months and in northern states.

Symptoms of E. coli infection

Symptoms can start from 1 to 10 days after you’re exposed to the germ. The first symptoms are severe abdominal cramps that start suddenly. After a few hours, watery diarrhea starts. The diarrhea causes your body to lose fluids and electrolytes (dehydration). This makes you feel sick and tired. The watery diarrhea lasts for about a day and then may change to bright red bloody stools. The infection makes sores in your intestines, so the stools become bloody. The bloody diarrhea may last for 2 to 5 days. You might have 10 or more bowel movements a day. Some people say their stools are “all blood and no stool.” You may have a mild fever or no fever. You may also have nausea or vomiting. If you have any of these symptoms—watery, bloody diarrhea, cramps, fever, nausea, or vomiting—try to get to your doctor right away.

Are there any complications from E. coli infection?

One uncommon but severe complication is called hemolytic uremic syndrome. People with this problem get hemolytic anemia (which is a low red blood cell count), thrombocytopenia (which is a low platelet count), and renal failure (which is kidney damage). Hemolytic uremic syndrome is more common in children. It can cause acute renal failure in children. This problem starts about 5 to 10 days after the diarrhea starts. People with this problem must go to a hospital for medical care.

What causes E. coli infection?

Most E. coli infections come from:

  • Eating undercooked ground beef (the inside is pink)
  • Drinking contaminated (impure) water
  • Drinking unpasteurized (raw) milk
  • Working with cattle
  • Eating food contaminated with animal feces (such as vegetables)

Healthy beef and dairy cattle may carry the E. coli germ in their intestines. The meat can get contaminated with the germ during the slaughtering process. When beef is ground up, the E. coli germs get mixed throughout the meat. That is why it is important to make sure ground meat is cooked all the way through. For beef steaks, a pink middle is still OK.

The most common way to get this infection is by eating contaminated food. You can be infected with the E. coli germ if you don’t use a high temperature to cook your beef, or if you don’t cook it long enough. When you eat undercooked ground beef, the germs go into your stomach and intestines.

The germ also can be passed from person to person in daycare centers and nursing homes. If you have this infection and don’t wash your hands well with soap after going to the bathroom, you can give the germ to other people when you touch things, especially food.

People who are infected with E. coli are very contagious. Children shouldn’t go to a daycare center until they have 2 negative stool cultures (proof that the infection is gone). Older people in nursing homes should stay in bed until 2 stool cultures are negative.

How is E. coli infection diagnosed?

The diagnosis is made by finding E. coli in a stool culture. If you have bloody diarrhea, see your doctor as soon as possible. Your doctor will do a culture to find out if you have E. coli in your intestines. The culture has to be taken in the first 48 hours after the bloody diarrhea starts.

Can E. coli infection be prevented or avoided?

You can help prevent this infection by handling and cooking meat in a safe way. For your protection, follow these rules:

  • Wash your hands carefully with soap before you start cooking and after.
  • Cook ground beef until you see no pink anywhere.
  • Don’t taste small bites of raw ground beef while you’re cooking.
  • Don’t put cooked hamburgers on a plate that had raw ground beef on it before.
  • Cook all hamburgers to at least 155°F. A meat thermometer can help you test your hamburgers.
  • Defrost meats in the refrigerator or the microwave. Don’t let meat sit on the counter to defrost.
  • Keep raw meat and poultry separate from other foods. Use hot water and soap to wash cutting boards and dishes if raw meat and poultry have touched them.
  • Don’t drink raw milk.
  • Keep food refrigerated or frozen.
  • Keep hot food hot and cold food cold.
  • Wash all fruits and vegetables, especially if eaten raw.
  • Refrigerate leftovers right away or throw them away.
  • People with diarrhea should wash their hands carefully and often, using hot water and soap, and washing for at least 30 seconds. People who work in daycare centers and homes for the elderly should wash their hands often, too. Using hand sanitizer is often not enough to kill the coli, so proper handwashing is absolutely necessary.

In restaurants, always order hamburgers that are cooked well done so that no pink shows.

E. coli infection treatment

There is no special treatment, except drinking a lot of water and watching for complications. Don’t take medicine to stop diarrhea unless your doctor tells you to do so. This medicine would keep your intestines from getting rid of the E. coli germ. If you are seriously dehydrated, you might need to go to the hospital to have fluids put into your veins with an IV.

Living with E. coli infection

As you are managing E. coli at home, get plenty of bed rest. Rest promotes recovery. Drink plenty of fluids to keep from being dehydrated. Stick to clear liquids and avoid drinks that have caffeine or alcohol. When you feel you are able to eat, start slowly. Try some crackers or toast. If that sets well, begin to add in other foods, but nothing too high in fiber for a while. Most people will be better in 6 to 8 days.

Questions to ask your doctor

  • How do I know what caused an coli infection?
  • How can I safely cook meat to prevent coli infection?
  • What are other ways besides undercooked ground beef that can cause coli infection?
  • If I think I have and coli infection what should I do and when should I call you?
  • How can I prevent dehydration if I have an coli infection?
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