Esherichia coli (E. Coli) in Cats – Symptoms and Treatment

What is Escherichia coli?   How do cats become infected?   What are the symptoms?   How is it diagnosed?   How is it treated?

Escherichia coli at a glance

  • Escherichia coli (E. coli) is a bacterial infection of the gastrointestinal tract, uterus and urinary tract affecting many species of animal including cats. Most of the time the bacteria reside in the GI tract without incident.
  • Cats become infected when the bacteria find their way from one part of the body to another, for example, urinary tract infections, or when a cat consumes food containing a pathogenic (disease causing) strain of the bacteria.
  • Symptoms depend on the location of infection, if the gastrointestinal tract is affected, vomiting, diarrhea, which may be blood tinged. If the uterus is affected, fever, loss of appetite, lethargy, and in some cases a discharge from the vagina.
  • E. coli is treated with antibiotics to kill the bacteria as well as supportive care including fluids and nutritional support.

e coli in cats

Image NIAID, Flickr

What is Escherichia coli? 

Escherichia coli (E. coli) is a bacteria which usually resides in the gastrointestinal tract of mammals (including cats and humans) without incident. There are hundreds of strains of E. Coli, most of which are harmless, however, some strains are pathogenic, resulting in sickness.

How do cats become infected with E. coli?

There are typically two modes of infection:

1) When normal gastrointestinal bacteria find their way to other parts of the body, such as with urinary tract infections.

2) When a cat consumes a pathogenic strain of E. Coli.

What are the symptoms of E. coli in cats?

Symptoms of E. Coli depend on the location and strain of the bacteria. The current health status of your cat can also play a role in the development of E. Coli with certain conditions such as diabetes, kidney disease and hyperadrenocorticism (Cushing’s syndrome) making them more prone to urinary tract infection.

Cats who undergo several heat cycles without pregnancy are at greater risk of developing pyometra (infection of the uterus).

Pathogenic E. Coli in the gastrointestinal tract can result in vomiting and diarrhea. Infection is usually acquired via the consumption of infected meat or water.

Symptoms of E. Coli vary depending on the location of the infection but may include:


  • Vomiting
  • Diarrhea, which may be blood tinged


Coli in the uterus of intact female cats can result in pyometra. Infection may be open or closed. With open pyometra, the cervix is open, allowing pus to drain out of the vagina. When the cervix is closed, bacteria become trapped in the vagina, making it harder to diagnose, although she may present with a distended abdomen. It is quite easy for E. Coli around the anus to ascend into in the urinary tract, especially in female cats.

Typical symptoms of infection include:

  • Frequent urination (passing only a small amount)
  • Blood in the urine
  • Pain urinating
  • Frequent genital licking

Newborn kittens can become infected with E. Coli via the mother’s milk, this usually happens within the first two weeks of life. This is known as colibacillosis. Other contributing factors include unclean environment, maternal health, crowded conditions.

As we have noted, symptoms vary depending on where the infection is located, but along with individual symptoms, you may also notice your cat displays the following:

  • Loss of appetite
  • Fever
  • Lethargy
  • Weight loss
  • Dehydration
  • Increased thirst

How is E. coli diagnosed?

Your veterinarian will perform a physical examination of your cat and obtain a medical history from you, including how long your cat has been sick and other symptoms you have noticed. As E. coli can cause infection in many parts of the body, presenting symptoms will give your vet a clue as to what the problem is.

He will want to run some diagnostic tests which may include:

  • Bacterial culture to test for the presence of bacteria. This may involve taking a sample of feces, blood, urine (urinalysis), pus from the vagina. Other types of bacteria can also cause infection, so identifying the particular type (E. Coli, Salmonella etc), is important.
  • Once identified, your veterinarian may decide to run an antibiotic sensitivity test, this involves growing the bacteria in a culture dish with a growth medium, and expose it to several types of antibiotics to determine which one the bacteria is most sensitive to.
  • Ultrasound may also be required to diagnose closed pyometra.
  • Biochemical profile may also be suggested to check for underlying disease (such as diabetes or kidney disease).

How is E. coli treated?

  • Antibiotics are the treatment of choice along with supportive care such as intravenous fluids to correct electrolyte imbalances and treat dehydration and nutritional support.
  • Newborn kittens are especially vulnerable and must be treated aggressively if they are to survive.
  • An entire female with pyometra should be spayed if not to be used for breeding.
  • If urinary tract infection has occurred, diligent care must be taken with litterbox maintenance to make sure it is clean at all times. Holding onto the urine along with inadequate water consumption are both contributing factors. Increasing water consumption should also be practiced. This may include feeding your cat a wet diet (which has a higher water content than dry food) and/or encouraging your cat to drink more water.