E. Coli in Cats

Escherichia coli, commonly known as E. coli, is a bacterium that lives in a normal, healthy cat's lower intestine. It’s found in most warm-blooded mammals as well, including humans.  

Aside from the intestinal tract, E. coli also causes disease in cats when it infects the urinary tract or the reproductive system. Colibacillosis is the term used when E. coli causes disease in cats and it can often lead to an infection of the bloodstream, a serious condition called sepsis or septicemia.

What Is E. Coli in Cats?

Kittens are the most common age group of cats that get E. coli infections due to their immature immune system. E. coli is commonly seen within the first few weeks of life.

When a newborn kitten nurses on their mother on the day they are born, they receive a milk called colostrum. Colostrum is rich in antibodies to help protect them. Kittens that do not have colostrum—which typically happens with orphaned cats—are more susceptible to E. coli infection due to a lack of maternal antibodies.

Older cats with compromised immune systems from other conditions are also often affected with E. coli.

Healthy adult cats rarely have any medical issues resulting from E. coli, even though they have these bacteria living in their lower intestine.

There are hundreds of different strains of E. coli, each causing different symptoms, but most do not cause illness. The vast majority of infections caused by E. coli occur when the bacteria is in other areas of the body where it shouldn’t be, or when a harmful strain is present.

Can Cats Spread E. Coli to Humans?

Both humans and animals are susceptible to E. coli infections. It can be spread from cats to humans and vice versa, even though humans most commonly get it from consumption of contaminated food such as raw or undercooked meat.

Cats spread E. coli by shedding the bacteria in their stool. People can accidentally get this bacterial infection if they get cat feces on their skin, don’t wash their hands effectively, and then eat or lick their fingers.

Cats rarely give people E. coli, but the most serious form of it cannot be spread from cats to humans, as humans most often contract it from livestock and deer meat. Unfortunately, animals do not have to be ill to spread E. coli; they can be a carrier and not show any signs.

Can Cats Spread E. Coli to Other Animals?

Similar to the way cats can spread E. coli to humans, it can be spread to other animals as well, but it is not common.

Causes of E. Coli in Cats

E. coli infections occur when the pathogenic (illness-causing) strains of the bacteria overpopulate. It is the bacteria that most commonly causes urinary tract infections (UTIs) in cats.

The bacteria travels from the intestinal tract out the body, through the anus, and can get into the urinary tract by ascending back into the body by external genitalia (penis or vagina).

The bacteria infect the gastrointestinal tract when a cat ingests undercooked or raw meat, similar to what happens with humans. Community cats are more susceptible to this form of E. coli due to hunting and eating prey, although any cat can get it from contaminated commercial cat food.

Raw food diets have also become increasingly popular in recent years, and this has caused a spike in food-borne illness in cats.

Another way cats become infected with E. coli is an overgrowth inside their uterus, seen in unspayed female cats. This growth is often triggered by hormonal influence and causes an infection in the uterus called a pyometra. Newborn kittens can develop an E. coli infection after exposure to this bacterium in their mother’s womb, during the birthing process, when nursing from an infected mammary gland, or when they are kept in unsanitary living conditions.

Newborn kittens are also susceptible if they have not nursed during the first day of life, because they will not receive helpful antibodies through colostrum.

Symptoms of E. Coli in Cats

The location within the body where E. coli is found will determine the symptoms.

Urinary tract infections:

• Increased frequency of urination

• Increased thirst

• Accidents outside of the litterbox

• Vocalizing during urination

• Blood in urine (hematuria)

• Odor in urine

• Straining to urinate where little-to-nothing comes out (stranguria)

• Painful and/or distended abdomen

• Elevated body temperature (fever)

• Decreased or full loss of appetite

Gastrointestinal infections:

• Watery diarrhea with or without blood

• Vomiting

• Decreased or total loss of appetite

• Depression

Pyometra (often after heat cycle when pregnancy did not occur):

• Vaginal discharge

• Decreased or total loss of appetite

• Distended and/or painful abdomen

• Increased thirst and/or urination (can mimic a urinary tract infection)

• Lethargy

• Depression

Colibacillosis in newborn kittens (sudden onset):

• Loss of appetite

• Vomiting

• Lethargy

• Severe diarrhea

• Low body temperature (hypothermia)

• Dehydration

How Do Veterinarians Diagnose E. Coli in Cats?

If you notice any signs of an E. coli infection in your cat, bring them to the vet for an exam with laboratory work as soon as possible. A thorough medical history of your cat will be taken, and your veterinarian will recommend the appropriate testing.

Your vet will also do an exam to assess your cat’s physical status and feel for anything irregular in the abdominal area, and may seek diagnostic testing such as:

• Bloodwork, such as a complete blood count and chemistry panel

• Urinalysis

• Stool analysis

• Vaginal swab

• Ultrasound of the abdomen

• X-rays

These tests will help your vet locate the area of E. coli infection and rule out any other medical issues that might cause the same or concurrent symptoms. At that point, a bacterial culture (samples taken from your cat; usually urine, stool, vaginal discharge, and/or blood) can be done to isolate the E. coli bacteria, which is used to give the most accurate diagnosis.

A sensitivity panel can be done on the same sample, in order to determine which antibiotics would best treat the infection.

Treatment of E. Coli in Cats

If your cat is not seriously ill, their E. coli infection can likely be treated on an outpatient basis. Antibiotics will be prescribed based upon the sensitivity panel results, and are usually given for 10 to 14 days or longer depending on the severity.

If your cat has an E. coli infection causing a pyometra, then surgery is the best treatment option to remove the uterus, which removes the infection. Pyometra can be life-threatening, so antibiotic treatment is very often not enough.

If your cat has severe signs, such as lack of appetite, dehydration, or prolonged vomiting, they will likely need hospitalization for treatment and supportive care.

IV fluids, antibiotics, and anti-nausea medications will be given, depending upon your cat’s clinical signs. If your cat isnot eating, a feeding tube might be considered, which can be lifesaving. Kittens also require aggressive treatment to maintain their blood sugar, as well as bottle feeding.

Is E. Coli Fatal in Cats?

E. coli infections can be fatal in cats if not treated promptly and aggressively. Infections in the blood (sepsis) or a pyometra are the most serious.

Recovery from E. Coli in Cats

Recovery time from an E. coli infection is based upon your cat’s treatment response. All medications must be given exactly as prescribed, for the appropriate amount of time, to ensure the infection is cleared.

A recheck of bacterial culture will often be done at the end of treatment to confirm there is no E. coli left behind. If your cat lives outdoors and they have acquired it from eating prey, they should only be kept inside to avoid spreading the disease and prevent it from recurring.

Prevention of E. Coli in Cats

Cats with a urinary tract infection will often be put on a usually lifelong special diet to help prevent the issue from recurring. Raw diets should also be avoided in cats, as contaminated meat is a common cause of E. coli—not only in cats but people, too.