E. Coli in Dogs

Rhiannon Koehler, DVM
By Rhiannon Koehler, DVM on Sep. 22, 2023
A yellow lab puppy gets a check-up from their vet.

In This Article


What Is E. Coli in Dogs?

The bacterium Escherichia coli, typically known as E. coli, is naturally found in the intestines of healthy dogs, on the skin, and in the environment. However, certain strains of E. coli can cause colibacillosis, an infection that is most often seen in young puppies.

E. coli has the potential to infect virtually any system within the dog’s body. In adult dogs, it most commonly causes urinary tract infections.

When humans think of E. coli, we often associate it with food poisoning. Although we don’t know how often E. coli causes diarrhea in dogs, it’s more common in dogs with underdeveloped or compromised immune systems, such as puppies.

An E. coli infection in a puppy can quickly progress to sepsis, which is a medical emergency. Seek veterinary care immediately if your pet is having severe diarrhea, repeated vomiting, loss of appetite, is collapsing or weak, or is having difficulty breathing.

Symptoms of an E. Coli Infection

E. coli infection in puppies usually comes on suddenly. Symptoms include:

E. coli can affect other body systems. While these symptoms refer to E. coli infections in puppies, E. coli can also cause pneumonia, urinary tract infections, pyometra (pus-filled uterus), and other illnesses.

Causes of E. Coli Infection

E. coli infections in puppies are most common within the first few weeks of life. Because puppies haven’t yet developed their own immune system, they are more susceptible to infection.

Puppies can become infected by E. coli in multiple ways:

  • The mom’s first milk after giving birth (colostrum) is usually rich in antibodies that protect puppies from disease. If the mom doesn’t produce enough good colostrum or the puppies aren’t nursing well, they’ll be more susceptible to infection because they won’t get sufficient antibodies from their mom.

  • If the mom has an E. coli infection, the bacteria can pass to the puppies while they are in her uterus, through the blood supply or during birth.

  • If the mom has E. coli in her milk or has an infected mammary gland (mastitis), this can lead to infection of puppies as they nurse.

E. coli infection may be more common in puppies born to dogs in unsanitary conditions, such as puppy mills or overcrowded kennels. Shelters may see more E. coli infections, as they often take in birthing or lactating mothers that haven’t received proper care.

Additionally, there are reports of dogs contracting antibiotic-resistant E. coli from consuming raw meat. This is especially concerning because the humans preparing the food are also at risk of exposure.

How Veterinarians Diagnose E. Coli Infection

In puppies that have E. coli symptoms, the veterinarian is likely to perform a fecal flotation test to check for parasites and perform a parvovirus (parvo) test, which involves testing a small sample of feces. If these tests yield negative results, the vet will usually begin aggressively treating the symptoms.

Confirmation of E. coli infection requires a culture. In adult dogs, cultures are more commonly performed for infections of specific body systems, such as the urinary tract. This ensures that the selected antibiotics effectively treat the infection.

In severe cases where the animal is suspected to have an infection that has spread through their bloodstream (sepsis), the veterinarian will conduct a blood culture. Animals with sepsis are critically ill and are usually treated at a specialty clinic.

Puppies with sepsis are often euthanized or die before the culture results are received. In most cases, veterinarians will aggressively initiate treatment without a definitive diagnosis and adjust the plan based on testing results.

Important information to provide your veterinarian includes:

  • Your dog’s vaccination history

  • Dewormers or preventatives you use

  • Medications your pet is taking

  • Recent changes in diet or nursing behaviors

  • Whether your pet eats raw meat

Treatment of E. Coli in Dogs

For dogs with severe diarrhea or dehydration, inpatient treatment with intravenous fluids is recommended. In mild cases, fluids may be given subcutaneously (under the skin) on an outpatient basis.

In severe cases of diarrhea leading to electrolyte imbalances or low blood sugar levels, electrolytes, and dextrose (a type of sugar) may be added to the fluids.

Dogs with a poor appetite, particularly puppies, may need a feeding tube.

Examples of medications that may be prescribed include:

The use of antibiotics in most cases of diarrhea is controversial. However, in young puppies where sepsis is a concern, antibiotics will be started. E. coli is generally susceptible to a range of antibiotics, including amoxicillin with clavulanic acid, doxycycline, and others.

Nevertheless, it’s relatively common for E. coli to be resistant to specific antibiotics, so treatment should be adjusted based on culture and sensitivity results whenever possible.

Recovery and Management of E. Coli in Dogs

Puppies with E. coli infection may need to be bottle-fed to maintain adequate nutrition, especially if the mother has mastitis. If a puppy won’t take the bottle and isn’t nursing, seek veterinary help with tube-feeding.

Puppies need to stay clean and warm. Regularly change their bedding and ensure you have clean hands and clean clothes when handling them.

While some puppies will recover over several days, despite intensive treatment many puppies can rapidly decline, sometimes within hours of showing symptoms.

Prevention of E. Coli in Dogs

While not all cases of E. coli are preventable, keeping a pregnant or nursing female healthy is important. If you have a breeding female, make sure to keep her in a sanitary environment. Regularly clean and change her bedding, and provide her with a high-quality, well-balanced diet.

Monitor the puppies for nursing behaviors after birth to ensure they are nursing properly. If you notice redness, sores, or pus on or near the mother’s teats, seek treatment promptly. It’s best to avoid letting puppies nurse from an obviously infected mammary gland. Remember to wash your hands and wear clean clothes before handling puppies.

If you feed your dog table scraps or a homemade diet, make sure that all meat is thoroughly cooked. After handling raw meat, wash your hands and clean all surfaces and utensils that have encountered it.

E. Coli in Dogs FAQs

How long can a dog live with E. coli?

Some puppies may recover from E. coli infection, while others can deteriorate rapidly within hours of showing symptoms. With proper supportive care, most adult dogs can overcome an E. coli infection and live a normal lifespan.

Is E. coli in dogs contagious to humans?

Yes. Contact with dogs or their feces is considered a risk factor for the development of E. coli infections in people.

Can you treat E. coli in dogs naturally?

Dogs with E. coli infection should be seen by a veterinarian. While many cases can be managed with supportive care and may not require intensive medical treatment, this treatment should be overseen by a veterinarian.

Featured Image: iStock.com/Vesnaandjic

Rhiannon Koehler, DVM


Rhiannon Koehler, DVM


Dr. Rhiannon Koehler is a veterinarian and freelance medical writer. She received her Doctor of Veterinary Medicine and Master of Public...

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