How E. coli infections happen and how you can prevent them with good hygiene and food safety

Escherichia coli (E. coli) is a group of bacteria that normally lives in the gut of healthy people and animals, and helps to digest food. Most kinds of E. coli bacteria are harmless, but there are some strains of E. coli that can release toxins and cause you to experience symptoms that range from mild to life threatening.

Here's how to distinguish between different types of E. coli infections, symptoms you may experience, how you can become infected, and how to treat and prevent illness from E. coli.

Types of E. coli infections range from mild to severe

There are hundreds of types of E. coli bacteria that exist. There’s even a type that lives in your gastrointestinal (GI) tract that helps you digest food. But depending on the type and circumstances, E. coli bacteria can be harmful and cause you to experience symptoms like diarrhea, stomach cramps, vomiting or fever.

For example, there are two common types that cause infections that are typically mild: Enterotoxigenic Escherichia coli (ETEC) and Uropathogenic Escherichia coli (UPEC). ETEC is a common cause of traveler’s diarrhea and UPEC is a common cause of urinary tract infections (UTIs).

Other types can cause:

• Bacterial infections in the blood like bacteremia and sepsis
• Cholecystitis (gallbladder infection)
• Meningitis and pneumonia, although this is rare
• Pelvic inflammatory disease (PID)
• Prostatitis (an infection in the prostate)
• Wound infections

Shiga toxin-producing E. coli (STEC)

When you hear about an E. coli outbreak, Shiga toxin-producing E. coli (STEC) is usually the reason, and it usually only causes mild illness. However, it can become very serious and even life threatening for a small number of people, causing hemolytic uremic syndrome (HUS).

HUS occurs most often in older adults who are infected with STEC. It’s a serious disease that can cause kidney damage or failure, and permanent health issues, especially if left untreated. It almost always requires hospitalization, and while most people recover within a few weeks, it can be fatal for others.

Symptoms of an E. coli infection

E. coli infections have similar symptoms to other illnesses caused by different bacteria, so it’s not always a straightforward diagnosis. Symptoms usually develop within 3-5 days of exposure, but depending on the strain of E. coli bacteria you’re infected with, symptoms can develop anywhere from 8 hours to 10 days.

The first sign of infection is usually watery diarrhea. Other common and less severe symptoms of an E. coli infection can include:

• Fatigue
• Loss of appetite
• Low fever (usually under 101^oF) and vomiting, although these are less common with mild infections
• Nausea
• Stomach pains and cramps

If E. coli bacteria has caused a UTI, symptoms can include abdominal pain, a burning sensation when you pee, cloudy and foul-smelling pee, and the need to pee often.

Severe symptoms of E. coli include:

• Diarrhea that lasts longer than 3 days
• Diarrhea with blood
• Dehydration
• A fever over 102^oF

If you’re experiencing severe symptoms, head to urgent care or call your doctor. They can confirm an E. coli infection with a stool sample. Serious cases of E. coli infection may require treatment in a hospital that includes IV fluids, blood transfusion and kidney dialysis.

How E. coli is transmitted and causes infection

E. coli bacteria is spread through poop particles so small that you can’t see them. The most common way to get an E. coli infection is through consuming contaminated foods and beverages. But it can also be spread in water, through person-to-person contact, and rarely through dust, like on farms.

Contaminated foods that can cause an E. coli infection include:

• Foods that have been prepared by people who haven’t practiced proper handwashing or proper food handling
• Raw fruits and vegetables that haven’t been washed thoroughly
• Undercooked ground beef
• Unpasteurized beverages like milk and certain types of juice

Water sources that can transmit infection include:

• Ground and surface water, like those used to irrigate crops
• Pools and lakes
• Private water sources, like wells, as there isn’t an easy way to disinfect them
• Public water works that are poorly maintained and disinfected

Other sources of infection include:

• Not wiping properly after a bowel movement, where poop can move into your urinary tract, causing a UTI
• Petting zoos, where a type of E. coli that’s found in the intestines of cows, sheep and goats can be spread from their poop to their fur or skin, and then to the hands of people petting them

E. coli is contagious and can be spread by touching infected surfaces

Unlike some bacteria, E. coli can’t be spread from sneezing or coughing. However, it can live on surfaces anywhere from hours to months, depending on the material. Transmission can happen due to:

• Touching contaminated surfaces, then touching your nose, mouth or face
• Changing contaminated diapers
• Sharing objects with an infected person

Risk factors for E. coli infections

Anyone can get an E. coli infection, but there are certain groups of people that are more susceptible. They include:

• Children younger than 5 years old
• Adults 65 years old and older (this group is most likely to develop HUS)
• International travelers
• People with certain health conditions like diabetes or ulcerative colitis
• People with weakened and underdeveloped immune systems
• People with decreased stomach acids

How long E. coli infection lasts

How long an infection lasts depends on the strain of E. coli you’re infected with. With STEC, diarrhea should not last more than 2-3 days, and healthy adults should feel fully recovered within a week. Children may feel better in a few days, but can still be contagious for up to 3 weeks.

Other infections, like the kind that causes traveler’s diarrhea, usually resolve on their own without treatment within a few days. And while UTIs can get better on their own, treatment with antibiotics may be necessary.

Treating E. coli if symptoms are severe

Treatment for an E. coli infection can usually be done at home. However, people more susceptible to HUS, the life-threatening form of kidney failure caused by E. coli bacteria, should seek treatment immediately.

For others, if your infection is causing GI issues like diarrhea, you don’t need to do anything special – symptoms will most likely go away on their own. But you can ease the symptoms of diarrhea by getting plenty of rest, drinking plenty of fluids and eating a bland diet.

Doctors don’t usually treat E. coli, especially STEC, with over-the-counter anti-diarrheal medicine or with antibiotics, even though it’s caused by a bacteria. This is because these medications increase the likelihood of developing HUS. Plus, anti-diarrheal medicines can delay the body’s attempts to get rid of the infection, so it’s better to let it run its course.

It’s relatively easy to avoid an E. coli infection, especially in the U.S. Being diligent about hygiene and properly preparing and consuming food are helpful ways to stay healthy. And since E. coli is considered a seasonal illness, it’s important to be vigilant in warmer months. E. coli infections tend to spike from June through September, when warmer weather helps E. coli bacteria grow and thrive.

Preparing your food properly at home can help avoid an E. coli infection

Proper handwashing before food prep is key to avoiding a lot of infections, and E. coli is no different. Other things you can do include:

• Thoroughly washing produce – You don’t need to buy any special products to wash your fruits and vegetables. It should be enough to rinse them under running water. However, E. coli can live in leafy greens, so it’s important to take special care when washing them. And don’t forget to wash produce even if it comes from your own garden. There’s always the possibility of contamination from backyard critters looking for a snack.
• Handling meat properly – Many people think that you need to wash your meat, like chicken, before you cook it. This could cause more harm than good, as contaminated water can spread droplets to nearby surfaces, utensils and even other food that’s being prepped. Cooking your food to its proper temperature should be enough to kill any bacteria on the meat.
• Sticking with pasteurized foods – Pasteurization kills bacteria like salmonella, listeria and E. coli. Avoid drinking any unpasteurized dairy or juice to lessen your chances of infection.
• Avoiding cross-contamination – During food prep, keep cutting boards and utensils separate.

Other important tips when it comes to cooking meat: ground beef should always be cooked to a temperature of 160^oF, don’t defrost meat at room temperature and always wrap meat in a bag while it’s defrosting.

Other ways to avoid E. coli in the home

While regular soap and warm water is your best protection against E. coli, bleach can be a good tool to have on hand too. Some things you can do in the home to prevent E. coli include:

• Washing your hands frequently – This includes before, during and after food prep, after you use the bathroom and after you change a diaper.
• Keeping your space sanitized – Regularly wash and sanitize any tool used in the kitchen, particularly those that are used frequently. Clean inside the drawers and the shelves of your refrigerator with bleach, especially if they held raw meat. And always thoroughly sanitize any countertops and cutting boards after using.
• Playing it safe with pets – Make sure you’re regularly washing and drying your pets’ dishes, and try to keep children and people with compromised immune systems away from dirty pet dishes.

Prevention outside the home is important

It’s not always possible to avoid places where E. coli is present, but there are things you can do to minimize your chance of infection:

• Make washing your hands a priority – This is especially important when using public bathrooms, as E. coli bacteria can live on surfaces for months. If you go to a place where there’s contact with animals, always wash your hands and your children’s hands thoroughly.
• Use your best judgement with water sources – E. coli can live and thrive in warm bodies of water, especially if they’re small and stagnant, including small ponds and backyard kiddie pools. Try to avoid these places if possible, and when using them, don’t ingest the water.
• Take precautions when traveling – If you’re in a country where you are unsure if the water is safe, use bottled or boiled water for drinking, brushing your teeth and cooking. And if you’re not sure of the source of produce, it’s best to avoid it as it could have come in contact with a contaminant.

When to call a doctor about an E. coli infection

In most cases, E. coli infections clear up on their own without treatment. But if you’re experiencing signs of dehydration, passing bloody stools or running a fever, call a doctor or visit an urgent care location. In more complex or rare cases, primary care doctors can connect their patients with an infectious disease expert.