E. Coli Infection in Cats – Symptoms, Diagnosis and Treatment

picture of a black cat

Escherichia coli is a bacterium that is commonly found in both animal and human urine and feces. All living mammals have a variety of bacteria in their digestive and urinary tract, and they don’t become pathogenic and start causing problems if the animal is completely healthy.

That is why the vast majority of cats never end up having an E. coli infection, especially if they are generally healthy. However, it can cause health problems in kittens and geriatric cats, whose immune systems are compromised to an extent.

Cats that have chronic health issues can also develop an E. coli infection, and while in most cases, it is fairly easy to treat, it can be complicated in others. In this post, we’ll look at the symptoms of this infection, its causes, diagnosis, and treatment.

What Causes an E. Coli Infection in Cats?

As we have noted already, all cats have a number of E. coli bacteria in their bodies, and most of them don’t develop any disease at all. But in some cases, E. coli is involved in the development of urinary infections (and others), especially in cats that aren’t capable of grooming, for example.

Whenever the bacteria grow and get to an abnormal level, no matter if this happens in the cat’s digestive or urinary tract, the animal is at risk of developing an infection.

Constipation is common in geriatric cats, and it puts them at a higher risk. There are a number of other bacteria and yeast that keep a balance inside the digestive tract, and the same goes for the urinary tract, too. If the feces remain inside the cat’s intestines for too long, they might become the perfect environment for a bacterial culture.

If your cat has been suffering from diarrhea, she could also develop an E. coli infection simply because, along with the feces themselves, there is a wide range of healthy bacteria and yeast being eliminated from the digestive tract.

Newborn kittens can develop an E. coli infection if it is passed to them from the mother either in the womb or during birth. They can also get it while nursing from the mammary glands if they are contaminated. Naturally, they can also get infected if they are kept in unhygienic conditions.


There are three main types of infection that this bacterium can cause in cats. One of the most common ones is a UTI, but it can also lead to a gastrointestinal infection, or it can affect the uterus of females, in which case it causes pyometra.

If the cat develops a urinary tract infection, she will urinate more often than usual, do so outside the litter box, or yowl while urinating. You will also be able to see blood in the urine, or the cat might develop a fever. Some cats are tender in their abdomen, so they will avoid being touched there at all costs.

When E. coli causes a gastrointestinal infection, the cat might show symptoms such as vomiting and diarrhea (some of which might contain blood), and might have no interest in food whatsoever.

Pyometra is a condition that more commonly occurs when the cat is in heat or right after a heat cycle. If Escherichia coli is the bacterium that causes the infection, you might notice clinical signs such as lethargy, increased thirst, panting, fever, or even vaginal discharge. Pyometra is a medical emergency, so take your cat to the vet right away if you notice any of these symptoms. Many cats die because of it.


There are several ways of determining whether a cat is suffering from an E. coli infection or not, but the vet will most likely first perform a physical examination and then recommend additional tests such as CBC, serum tests, a urinalysis, a vaginal swab, or a fecal exam.

If other conditions are suspected, too, the cat might have to go through extra tests, such as an X-ray or an ultrasound.

In any case, a clear diagnosis can only be made if a bacterial culture and an antibiotic sensitivity test are performed, too. The bacterial culture reveals the specific germ that has caused the infection and the antibiogram reveals the appropriate treatment.

Treatment of E. coli infections in cats

Even though the majority of E. coli infections in our feline friends are easy to treat, especially when they haven’t gotten to a severe stage, a correct treatment plan usually calls for the last two diagnostic techniques that we have mentioned.

Once the vet finds out to which antibiotic the exact strain of E. coli that’s at the root at the infection is sensitive to, they will be able to prescribe the appropriate therapy. In some cases, vets prescribe broad-spectrum antibiotics and they work, but it is extremely important for you to administer the meds to your cat without missing a day out of the 10 to 14 ones recommended.

If the cat has a worsened health condition due to the infection, she might have to receive IV fluids to treat hypoglycemia or dehydration and might have to be hand-fed for a while. Kittens that develop this type of infection will have to be warmed up if they suffer from hypothermia.


As previously mentioned, most cats have an excellent chance of recovering from an E. coli infection over the span of a couple of weeks.

Giving your cats the antibiotics as per the vet’s recommendations is paramount. If you stop at one point and think that your cat is well again, there is a chance that the infection might recur. Not only that, but the next time around, the bacteria might be resistant to the antibiotics that you have previously used.

In both animals and people, antibiotic resistance is an issue that medical professionals are being confronted with every day. That is why giving your cat the antibiotics for the whole duration of the treatment is so important.



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