E. coli Infection

Topic Overview

What is an E. coli infection?

E. coli is the name of a germ, or bacterium, that lives in the digestive tracts of humans and animals.

There are many types of E. coli, and most of them are harmless. But some can cause bloody diarrhea. The most common type is called E. coli O157:H7. In some people, this type of E. coli may also cause serious blood problems or kidney failure, which can lead to death.

Other strains of E. coli can cause urinary tract infections or other infections.

What causes an E. coli infection?

You get an E. coli infection by coming into contact with the feces, or stool, of humans or animals. This can happen when you drink water or eat food that has been contaminated by feces.

E. coli in food

E. coli can get into meat during processing. If the infected meat is not cooked to 160°F (71°C), the bacteria can survive and infect you when you eat the meat. This is the most common way people in the United States become infected with E. coli. Any food that has been in contact with raw meat can also become infected.

Other foods that can be infected with E. coli include:

• Raw milk or dairy products. Bacteria can spread from a cow's udders to its milk. Check the labels on dairy products to make sure they contain the word "pasteurized." This means the food has been heated to destroy bacteria.
• Raw fruits and vegetables, such as lettuce, alfalfa sprouts, or unpasteurized apple cider or other unpasteurized juices that have come in contact with infected animal feces.

E. coli in water

Human or animal feces infected with E. coli sometimes get into lakes, pools, and water supplies. People can become infected when a contaminated city or town water supply has not been properly treated with chlorine or when people accidentally swallow contaminated water while swimming in a lake, pool, or irrigation canal.

E. coli from person-to-person contact

The bacteria can also spread from one person to another, usually when an infected person does not wash his or her hands well after a bowel movement. E. coli can spread from an infected person's hands to other people or to objects.

What are the symptoms?

Bloody diarrhea is the main symptom of an E. coli infection. You may also have stomach cramps and nausea and vomiting. Some people do not notice any symptoms. Children are more likely than adults to have symptoms. Symptoms usually start 3 or 4 days after you come in contact with the E. coli germ.

Most people get better in about a week. They often don't see a doctor and don't know that E. coli caused their problems.

When the germ causes serious problems with the blood or kidneys, symptoms include:

• Pale skin.
• A fever.
• Weakness.
• Bruising.
• Passing only small amounts of urine.

How is an E. coli infection diagnosed?

Your doctor may suspect that you have an E. coli infection after he or she asks you questions and does an exam. Your stool will probably be tested for E. coli.

How is it treated?

E. coli infection usually goes away on its own. Your main treatment is to make yourself comfortable and drink sips of water. Diarrhea causes the body to lose more water than usual. This can lead to dehydration, which is especially dangerous for babies and older adults. Taking frequent, small sips of water will help prevent dehydration.

If you have diarrhea that you think may be from an E. coli infection, do not take diarrhea medicine. It can slow down the digestion process, allowing more time for your body to absorb the poisons made by the E. coli germs. Call your doctor instead.

In some people, E. coli infection causes serious problems with the blood and kidneys. These people may need blood transfusions or dialysis. Dialysis is a treatment that helps filter waste products from the blood when the kidneys aren't working right.

How do you prevent an E. coli infection?

Food and water that are infected with E. coli germs look and smell normal. But there are some things you can do to prevent infection:

• Cook all types of beef, but especially ground beef, to at least 160°F (71°C).
• In the kitchen, wash your hands with hot, soapy water often, especially after you touch raw meat.
• Wash any tools or kitchen surfaces that have touched raw meat.
• Use only pasteurized milk, dairy, and juice products.
• Use only treated, or chlorinated, drinking water.
• When you travel to developing countries, don't use ice or drink tap water. Avoid raw fruits and vegetables, except those with skin that you peel yourself.
• Wash your hands often, and always wash them after you use the bathroom or change diapers.

Frequently Asked Questions

Learning about E. coli infection:	What is an E. coli infection? What causes it? How does it spread? Who is affected by E. coli infection?
Being diagnosed:	What are the symptoms of an E. coli infection? How is it diagnosed?
Getting treatment:	How is an E. coli infection treated? What can I do to treat it at home?
Ongoing concerns:	What can I do to prevent an E. coli infection? What are health officials doing to control E. coli?

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Author:	Ralph Poore	Last Updated: June 27, 2006
Medical Review:	Adam Husney, MD - Family Medicine Kathleen Romito, MD - Family Medicine W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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