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Escherichia coli (E. coli) Infections


The Manual's Editorial Staff

Reviewed/Revised Jul 2023
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What is E. coli?

Escherichia coli, often called simply E. coli, is a group of bacteria Overview of Bacteria Bacteria are microscopic, single-celled organisms. They are among the earliest known life forms on earth. There are thousands of different kinds of bacteria, and they live in every conceivable... read more . There are different types of E. coli. Some types normally live in your intestines. If these E. coli get into other parts of your body, you can get sick. If other types of E. coli get into your intestines, you can also get sick.

See a doctor right away if you have diarrhea that is bloody or happens with a fever.

What causes E. coli infections?

You can get an E. coli infection in your intestines if you:

  • Eat food that has E. coli bacteria in it

  • Touch animals that have an E. coli infection

  • Drink water that has E. coli in it, especially in lakes, ponds, streams, or pools

Cooked food can have E. coli in it if it wasn't cooked properly. Fresh food, such as salads, can have E. coli if it was washed in dirty water.

Touching animals in petting zoos sometimes spreads E. coli.

E. coli O157:H7

E. coli O157:H7 is a type of E. coli that can infect your colon (your large intestine) and cause colitis. Colitis is irritation and bleeding in your colon.

You can get E. coli O157:H7 infection the same way as other E. coli infections.

What are the symptoms of E. coli infections?

Symptoms depend on the part of your body that's infected and the type of E. coli you have.

Infections in your intestines can cause:

  • Brief, watery diarrhea

  • Cramps in your belly

  • Feeling sick to your stomach and throwing up

E. coli O157:H7 infections in your intestines can also cause blood in your stool (poop).

Infections in your urinary tract and bladder can cause:

  • Having to urinate (pee) often

  • Pain and burning while urinating

How can doctors tell if I have an E. coli infection?

Doctors do tests to look for E. coli by taking samples of your blood, urine, stool, or other infected materials. Your doctor will send the samples to a lab. The lab will test the samples to see what type of E.coli you have and which antibiotics may kill it.

How do doctors treat E. coli infections?

If you have traveler's diarrhea from an E. coli infection in your intestines, your doctor may have you:

  • Drink lots of fluids

  • Take a medicine that slows down diarrhea

  • Take antibiotics, if you have a lot of diarrhea

Your doctor won't have you take antibiotics if your diarrhea is bloody.

If you have an E. coli infection in your bladder, urinary tract, or elsewhere in your body, your doctor will have you:

  • Take antibiotics

How can I prevent E. coli infections?

  • Wash your hands after you use the bathroom or change a diaper

  • Always wash your hands, counters, cutting boards, and utensils after you touch raw meat

  • Cook beef to a temperature of 160°F (71°C) or higher before eating it—usually gray or brown inside, not pink or red

  • Avoid raw milk, other dairy products, and juices that aren’t pasteurized (a heat treatment that kills bacteria)

  • Avoid swallowing water in lakes, ponds, streams, or pools

  • Women should wipe from front to back and avoid the use of tight underwear to help prevent urinary tract and bladder infections

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