E. coli Infection

E. coli is a group of bacteria that can cause infections in your gut (GI tract), urinary tract and other parts of your body. Most of the time, it can live in your gut without hurting you. But some strains can make you sick with watery diarrhea, vomiting and a fever. Shiga toxin-producing E. coli (STEC) is most likely to cause severe illness.


Symptoms of an E. coli infection include watery diarrhea, nausea, vomiting, stomach pains, low fever and fatigue.
Most people associate E. coli with digestive symptoms. Outbreaks sometimes cause severe illness, including bloody diarrhea.

What is E. coli?

Escherichia coli (E. coli) is a group of bacteria that normally lives in the gut (gastrointestinal/GI tract) of healthy people and animals. The type that lives in your GI tract usually doesn’t hurt you — it even helps you digest your food. But under certain circumstances, many strains (types) of E. coli can make you sick. Many of the strains that cause infection can adhere (stick) to your cells and release toxins.


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What is an E. coli infection?

An E. coli infection is any illness you get from strains of E. coli bacteria. For instance, there are harmful strains of E. coli that cause watery diarrhea, stomach pain and other digestive symptoms (gastroenteritis) if you accidentally ingest them. These are sometimes called diarrheagenic E. coli, and they’re often what people mean when they talk about E. coli infections. But the E. coli that usually live in your gut can also get in places they’re not supposed to be (like your urinary tract). This causes an E. coli infection there.

Many strains of E. coli cause mild infections. But some strains, like those that produce Shiga toxin, can cause serious illness, including kidney damage.

Types of E. coli infection

Common types of E. coli infection include gastrointestinal and urinary tract infections (UTIs). Other types of E. coli infections include:

How common are E. coli infections?

There are about 265,000 Shiga toxin-producing E. coli (STEC) infections each year in the U.S. STEC is the most common cause of E. coli outbreaks and serious illness from E. coli in the U.S.

Symptoms and Causes

What are the symptoms of an E. coli infection?

Symptoms of E. coli gastroenteritis include:

  • Diarrhea. This is often watery and sometimes bloody.
  • Stomach pains and cramps.
  • Loss of appetite.
  • Low fever.

Watery diarrhea is usually the first symptom of an E. coli infection in your GI tract. You can also have different symptoms depending on where in your body you’re infected.

What are symptoms of E. coli in your urinary tract?

If E. coli infects parts of your urinary tract, you might have:

  • Abdominal or pelvic pain.
  • Pain or burning sensation when you pee.
  • An urgent need to pee frequently.
  • Cloudy, foul-smelling pee.

How soon do symptoms of an E. coli infection start?

You usually develop symptoms of an STEC infection within three to five days after drinking or eating foods contaminated with this E. coli bacteria. Other strains can make you sick within hours. Sometimes, symptoms start up to 10 days after exposure.


What causes E. coli infections?

Many strains of E. coli can cause diarrheagenic infections in your GI tract. Most cause similar symptoms, like watery diarrhea, but some are more serious than others. Scientists categorize them by how they attach to your cells and the types of toxins they release.

Types of diarrheagenic E. coli include:

  • Shiga toxin-producing E. coli (STEC).
  • Enterotoxigenic E. coli (ETEC).
  • Enteropathogenic E. coli (EPEC).
  • Enteroaggregative E. coli (EAEC).
  • Enteroinvasive E. coli (EIEC).
  • Diffusely adherent E. coli (DAEC).

Other notable types of E. coli include uropathogenic E. coli (UPEC), which can cause UTIs, and E. coli K1, which can cause meningitis in newborns.

What are Shiga toxin-producing E. coli (STEC)?

STEC is a strain of E. coli that releases a toxin (Shiga toxin) that damages your cells. These are the same toxins released by Shigella bacteria. STEC is known for causing severe outbreaks of E. coli (where many people get sick), often from contaminated food.

STEC is also called enterohemorrhagic E. coli (EHEC) because it can lead to bleeding in your intestines, causing bloody diarrhea (hemorrhagic colitis). About 5% to 10% of people with STEC develop hemolytic uremic syndrome (HUS), a condition that causes blood clots and damages your kidneys. The subtype E. coli O157:H7 is the most likely to cause severe illness.

What kind of E. coli causes traveler’s diarrhea?

Enterotoxigenic E. coli (ETEC) is a type of E. coli that causes infections known as traveler’s diarrhea. Symptoms start quickly after exposure — sometimes within just a few hours. ETEC is common in warm climates.

How do you get E. coli?

Most diarrheagenic E. coli strains spread through fecal-oral transmission. This happens when bacteria from poop that’s too small to see make their way into your mouth and digestive tract. Some forms, like STEC, can also transmit through undercooked meat and unpasteurized beverages.

Specifically, you can get E. coli from:

  • Eating contaminated foods. This includes undercooked meat and raw fruits and veggies that aren’t washed well enough.
  • Drinking unpasteurized beverages. This includes milk, cider or juice (and foods made from them, like cheese or ice cream).
  • Drinking contaminated water (or getting it in your mouth). E. coli in poop from animals and people can contaminate natural water sources (like lakes, streams and rivers), swimming pools and drinking water that isn’t sanitized.
  • Touching poop or contaminated surfaces. You can get poop on your hands from changing diapers, wiping after a bowel movement, touching petting zoo or farm animals, or sharing objects or surfaces with someone with an E. coli infection. You can swallow E. coli when it transfers from your hands to your mouth.
  • Not wiping properly after going to the bathroom. This can move E. coli from your poop to your urinary tract, causing a UTI.

Babies sometimes get E. coli infections during birth.

Is E. coli contagious?

Yes, E. coli can be contagious (spread from person to person). While you don’t get it from sneezing or coughing, you can get it from caring for someone with an E. coli infection, especially if you come in contact with their poop. You can also get it from objects, surfaces or food someone with an E. coli infection has touched if they don’t wash their hands well enough.

Who’s at risk for E. coli?

Anyone who comes into contact with a disease-causing strain of E. coli can get infected. People who are at greatest risk include:


What are the complications of E. coli infections?

E. coli sometimes causes life-threatening complications, including:

  • Hemolytic uremic syndrome (HUS).
  • Sepsis, a serious reaction to an infection in your bloodstream.
  • Malnutrition or delayed growth. Kids with chronic diarrhea may not be able to absorb the nutrients they need to grow.

Diagnosis and Tests

How is E. coli diagnosed?

How your provider diagnoses E. coli depends on what your symptoms are. If you have diarrhea or other digestive symptoms, your provider will test a stool (poop) sample for E. coli. If you have other symptoms, they might test your urine (pee), blood or cerebrospinal fluid (CSF).

What tests will be done to check for E. coli?

Specific tests for E. coli include:

Management and Treatment

How are E. coli infections treated?

You often don’t need to treat E. coli infections that cause digestive symptoms. Healthcare providers specifically don’t treat STEC with antibiotics or antidiarrheal medicines. These medications can increase your risk of HUS if you have STEC. Instead, they’ll monitor your condition and give you fluids to prevent dehydration if needed.

But if you have another type of E. coli infection — like a UTI, meningitis or sepsis — or if your symptoms are severe, your provider will treat you with antibiotics.

Antibiotics for E. coli infections

Some antibiotics providers use to treat E. coli infections include:


Can you prevent E. coli infections?

The most important thing you can do to protect against E. coli infections is to wash your hands. It’s particularly important to wash them thoroughly with warm water and soap:

  • Before and after cooking and after handling raw meat or poultry.
  • After using the restroom, changing diapers or contact with animals.

You can also reduce your risk of an E. coli infection by following safe food preparation procedures:

  • Don’t drink unpasteurized milk or ciders.
  • Rinse all raw fruits and vegetables under running water before eating them.
  • Don’t defrost frozen meat unwrapped on the counter. Keep frozen meat in a separate plastic bag when thawing.
  • Don’t rinse meat before cooking. Washing the meat could spread bacteria to nearby surfaces, utensils and other food.
  • Use a plastic, silicone or ceramic cutting board to cut raw meat. Wooden cutting boards are harder to clean completely, leaving bacteria behind.
  • Use different surfaces for prepping different types of food. Surfaces like cutting boards can spread bacteria. If you don’t have different cutting boards, wash surfaces thoroughly with soap and hot water after you’ve worked with raw meat and before putting another type of food (such as a raw vegetables) on it.
  • Cook all meat to a safe temperature before eating. Don’t put cooked meat on a plate that had raw meat on it.
  • Refrigerate leftovers right away.

Outlook / Prognosis

What can I expect if I have E. coli?

E. coli infections can cause everything from brief bouts of diarrhea to life-threatening illness. Most people recover on their own or with antibiotic treatment. Providers usually don’t treat STEC infections, but you might need supportive care, like supplemental fluids or nutrition. You might also be hospitalized and isolated to keep STEC from spreading.

How long does E. coli last?

Depending on the type of E. coli infection you have, your symptoms can last from two days to two weeks. STEC infections usually last five to seven days.

Will an E. coli infection go away on its own?

Mild E. coli gastroenteritis and some UTIs caused by E. coli can go away on their own. Recovery can take about a week without any treatment. But you should always check with a provider if you have severe or long-lasting diarrhea, abdominal pain, pain when you pee, or are peeing very little.

Can you die from E. coli?

Yes, E. coli infections can be deadly. Studies suggest the mortality (death) rate for E. coli infections is around 17%. But the results of these studies vary widely (from 8% to 35%). In general, E. coli UTIs are less likely to be fatal than other kinds of E. coli infections.

Sepsis is the most common cause of death in people with E. coli infections. People who are younger than 1 or older than 44, who have a respiratory infection, or who have an infection that doesn’t respond to antibiotics have higher mortality rates.

Living With

How do I take care of myself?

Don’t eat or drink anything that makes diarrhea worse, like caffeine or alcohol. Drink plenty of fluids to stay hydrated. If a provider has diagnosed you with STEC (especially E. coli O157:H7), don’t take anti-diarrheal medications like bismuth subsalicylate (Pepto-Bismol®, Kaopectate®) or loperamide (Imodium®). These medications can increase your risk of HUS.

When should I see my healthcare provider?

See a healthcare provider if you have diarrhea for more than three days, symptoms of a UTI or other health concerns.

When should I go to the ER?

Go to the nearest emergency room or seek immediate medical care if you:

  • Can’t keep any fluids down.
  • Have bloody diarrhea.
  • Are vomiting frequently.
  • Have a fever higher than 103 degrees Fahrenheit (40 degrees Celsius).
  • Are peeing (urinating) very little.
  • Have confusion or have other mental changes.
  • Are very weak or lethargic.

What questions should I ask my doctor?

It might be helpful to ask a healthcare provider:

  • What medications are safe for me to take?
  • What strain of E. coli do I have?
  • How can I prevent E. coli from spreading?
  • How can I prevent this in the future?

A note from Cleveland Clinic

E. coli is one of the many bacteria that can live in our bodies without harming us. But some strains can make us sick, especially if they get into places they aren’t supposed to be. Many E. coli infections can go away on their own. See your provider if your symptoms last more than a few days or are severe.

Medically Reviewed

Last reviewed on 11/22/2023.

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