What happens if e coli goes untreated

Key facts

  • E. coli (Escherichia coli) are a group of bacteria that are found in the gut of nearly all people and animals. Some E. coli bacteria can cause serious illness, and some cause no illness at all.
  • E. coli infection can be spread through contact with contaminated food or water, or with people who are sick.
  • The bacteria can cause diarrhoea and food poisoning, or more serious illnesses like pneumonia.
  • You can reduce your chance of E. coli infection by avoiding risky foods and practising good hygiene.


On this page

  • What is E. coli?
  • Minor illnesses caused by E. coli
  • Serious illnesses caused by E. coli
  • How could I get infected?
  • When should I see my doctor?
  • How is E. coli diagnosed?
  • How is E. coli treated?
  • Can E. coli be prevented?
  • Related information on Australian websites

What is E. coli?

E. coli (Escherichia coli) are a group of bacteria that are found in the gut of nearly all people and animals. There are many different strains of E. coli. Some cause no illness at all. Others cause minor illness, and yet others cause serious illness.

Minor illnesses caused by E. coli

Some strains of E. coli cause a range of minor illnesses including:

  • traveller’s diarrhoea and food poisoning, both of which can cause diarrhoea, stomach pain, nausea and vomiting, usually lasting less than 5 to 10 days
  • urinary tract infection, which can cause pain or a burning feeling when urinating, or make you feel you need to urinate frequently, or cause blood in the urine

Serious illnesses caused by E. coli

Some strains of E. coli cause serious illnesses such as:

  • pneumonia
  • meningitis in newborn babies
  • inflammation of the gallbladder (cholecystitis)

Haemolytic uraemic syndrome

E. coli can also cause a serious illness known as haemolytic uraemic syndrome, which damages the blood cells and can cause the kidneys to fail. Symptoms include:

  • dehydration
  • reduced urination
  • lethargy
  • pale skin (due to anaemia)
  • yellow skin and eyes (due to jaundice)
  • puffiness from fluid retention
  • seizures (fits)

Elderly people, young children and people with a compromised immune system are at greatest risk contracting a severe disease.

How could I get infected?

You can pick up E. coli infections in many different ways. You can get it from:

  • contact with contaminated food such as meat (especially undercooked minced meat in hamburgers), unpasteurised dairy products (such as raw milk) and fruit juices, and unwashed raw fruit and vegetables
  • contact with contaminated water, especially in rural areas or in swimming pools
  • personal contact with people who are sick (especially from their vomit or faeces) or from direct contact with animals who carry the bacteria

When should I see my doctor?

See your doctor if:

  • you have diarrhoea that is severe or has blood in it
  • you have a high fever with your diarrhoea
  • you have symptoms of haemolytic uraemic syndrome
  • the diarrhoea lasts for more than 2 days in an adult, or for more than 24 hours in a baby
  • you get dehydrated
  • you have severe pain in your abdomen or rectum
  • you have signs of a urinary tract infection
  • you are worried that you might have pneumonia
  • you are concerned that your baby is unwell

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How is E. coli diagnosed?

Formal diagnosis of E. coli infection usually requires laboratory testing of a stool (poo) specimen for the bacterium or the toxic chemicals it releases.

A blood test could also help to check for antibodies to the infection, haemolytic uraemic syndrome, or sepsis — a serious blood infection caused by bacteria, including E. coli.

How is E. coli treated?

Treatment for E. coli depends on what part of the body is infected and how serious the illness is.

If you have diarrhoea and are not very sick, keep hydrated by drinking plenty of fluids such as oral rehydration solution, which is available from pharmacies. If you don’t have a rehydration drink, you can use these drinks after diluting them.

  • Juice or soft drink: mix 1 part drink to 4 parts water (for example, 40 ml drink with 160 ml water).
  • Cordial: mix 1 part cordial to 20 parts water (for example, 5 ml cordial with 100 ml water).

Don’t take anti-vomiting or anti-diarrhoeal medications unless your doctor has recommended them. Most people recover within 5 to 10 days without treatment.

Can E. coli be prevented?

You can reduce your chance of E. coli infection by avoiding risky foods and practising good hygiene. Always wash your hands after going to the toilet or changing a nappy.

It is important to prepare, cook and store your food safely.

Safe food handling will avoid transmitting the infection from one food item to another — for example, from infected raw meat to fresh food. Washing fruits and vegetables that you’ll be eating raw in clean water will also reduce any E. coli contamination.

If you have been sick due to E. coli infection, you can also take steps to avoid infecting others.

  • Wash any bedding, clothing or household surfaces that have been dirtied by diarrhoea or vomit.
  • Avoid preparing food for others in your household for 24 hours after any symptoms disappear.
  • Stay away from work, or keep your child home from childcare or school, until at least 24 hours after any symptoms disappear (48 hours if you work in a care setting or handle food).

How long can E. coli last untreated?

Most people recover from E. coli infection without treatment within five to 10 days. Antibiotics should not be used to treat this infection because they may lead to kidney complications. Antidiarrheal treatments should also be avoided.

What happens if you don't get treated for E. coli?

Most healthy adults recover from E. coli illness within a week. Some people — particularly young children and older adults — may develop a life-threatening form of kidney failure called hemolytic uremic syndrome.

What are the long term effects of E. coli?

People who drink Escherichia coli–contaminated water and develop gastroenteritis increase their long-term risk of developing high blood pressure, heart disease, or kidney problems, according to a recent study.

What are the first signs of E. coli?

Symptoms of E. coli O157 infection include severe diarrhea (often bloody) and abdominal cramps. Most people infected with E. coli O157 do not have a fever or vomiting.