Key Points

  • Cat bladder infections are caused by bacteria and rarely, fungus.
  • Bacterial bladder infections are uncommon in cats and are more likely to occur in senior and female cats.
  • A positive urine culture test is required to differentiate bacterial bladder infections from the more common FIC.

Although cat owners tend to call all bladder symptoms a bladder infection, the term specifically refers to bacterial infections that can wreak havoc on your pet’s health. Cat bladder infections can cause discomfort and pain. They can even lead to severe complications if not treated promptly. 

Unlike sterile bladder inflammation, bacterial bladder infections are not common in cats. But the symptoms of both are nearly identical but the causes and treatment differ. 

Early veterinary care can differentiate between sterile bladder inflammation and bladder infection. With proper treatment, your cat can avoid the discomfort of either disease. 

This article will discuss cat bladder infections caused by bacteria. 


A bladder infection in cats occurs when a microorganism, usually bacteria, enters and multiplies in the urinary bladder. 

Other terms used for the condition

  • Lower urinary tract infection
  • Urinary tract infection
  • UTI
  • Cystitis
  • Bacterial cystitis

What is the difference between feline idiopathic cystitis and bacterial infection of the bladder?

Feline idiopathic cystitis (FIC), also known as feline lower urinary tract disease (FLUTD), happens when a cat’s bladder is inflamed but not infected with bacteria. The causes of FIC are unknown. 

FIC and UTI share many of the same symptoms. The only way to tell the two problems apart is with diagnostic testing. 

Treatment for FIC is different from treatment for UTI. Antibiotics do not help FIC and may cause unwanted side effects such as diarrhea and vomiting.

Risk Factors

Bacterial bladder infections are more likely to occur in females and senior cats. Martinez-Ruzafa et al. found the following factors increased a cat’s risk of getting a UTI (2)

  • Urinary incontinence
  • Transurethral procedure
  • Surgery of the urinary tract
  • GI tract disease
  • Decreased body weight
  • Decreased urine specific gravity (watery urine)

Kidney disease, diabetes mellitus, hyperthyroidism and bladder stones are associated with an increased risk of UTI in cats. (3)

Immunosuppressive drugs like prednisone and cyclosporine have not been found to increase the risk of UTI in cats. Immunosuppressive diseases such as FeLV and FIV are not known to increase ta cat’s risk of UTI. 

How common is it?

Bladder infections are uncommon in cats. In a 2019 paper published in the Journal of Feline Medicine and Surgery, Dorsch, R et al. state that bacterial bladder infections account for 2-19% of cases in all cats showing lower urinary tract symptoms. (1) And in younger cats, infections cause only about 3% of bladder-related symptoms. 

In other words, cats with bladder symptoms are much more likely to be suffering from FIC rather than a bacterial lower urinary tract infection.

How does this condition affect my cat’s body?

Bacterial UTIs can cause pain and discomfort. In some cases, the infection can spread to other parts of the body causing fever and occasionally organ failure. 


Most bacterial infections occur due to a decrease in a cat’s defense mechanisms. Usually, bacteria enter a cat’s bladder from the outside of the body. This is more likely in the case of poor urethral sphincter function and urinary catheterization or other surgery. 

Once bacteria arrive in the bladder, dilute urine and insufficient immune response may allow them to multiply. Some bacteria are stronger than others and more likely to survive in a cat’s bladder. Most of the time, these organisms come from the cat’s feces and/or skin. 

The most common bacteria to cause cat bladder infections are

  • E. coli
  • Staphylococcus species
  • Enterococcus species


Not all cats with bladder infections have symptoms. When cats do have symptoms here’s what you’ll see…

Mild SymptomsSevere Symptoms
Frequent urination, often with strainingPoor appetite
Passing smaller or larger amounts of urine than normalVomiting
Urine with an abnormally foul odorUnable to pass any urine
Licking genitalsLethargy
Vocalizing while urinatingDehydration
Urinating outside litterbox 

All of these symptoms can occur in cats who do not have a bladder infection but have FIC instead. Cats with FIC are more likely to have severe symptoms if they have a urethral blockage.

Remember: it is not possible to differentiate between FIC and UTI based on symptoms alone. Your veterinarian needs to do testing to make an accurate diagnosis. 

Are cat UTIs contagious?

Bacterial lower urinary tract infections in cats are rarely contagious to other cats, humans or other animals. 

white and orange long-haired cat (cat bladder infections)


A positive urine culture test is required to make a diagnosis of bacterial UTI. A urinalysis with increased white blood cells and changes to normal pH can be used as supporting evidence.

Essential tests for diagnosing UTIs in cats include urinalysis and urine culture. Urinalysis checks for red and white blood cells in the urine, urine pH, concentration of urine, urine glucose, urine protein and for the presence of crystals. 

A culture test checks for the presence of bacteria. Normal microorganisms from the lower urethra and genitals can contaminate urine samples from natural urination. That’s why a sterile urine sample is usually collected directly from the bladder using a hypodermic needle. 

Other tests that may be done 

  • Abdominal x-rays and/or ultrasound imaging
  • Blood chemistry, CBC, and thyroid tests
  • Biopsy/culture of the urinary bladder


Bacterial infection of the urinary bladder in cats is treated with antibiotic drugs. The drug is chosen based on the bacteria’s sensitivity pattern determined from the urine culture. 

After a period of antibiotic treatment, your vet may recommend rechecking the urinalysis and urine culture to make sure the infection is gone. 

It’s also important to treat underlying diseases such as kidney insufficiency, diabetes mellitus, hyperthyroidism and urine incontinence. 

Will a special diet help?

There is no specific cat food available to treat a bladder infection. In some cases, a special diet might keep a UTI from recurring after treatment. Depending on the circumstances your cat might benefit from a diet made for urinary crystal prevention, renal disease, hyperthyroidism, diabetes mellitus or gastrointestinal disease

What medications can help?

Antibiotics are the primary medication used to treat cats with UTIs. Your veterinarian may also recommend pain medication such and non-steroidal anti-inflammatory drugs or opioids. 

Some vets prescribe cranberry-based supplements with the thought that they may stop UTIs from recurring. However, scientific evidence to support the use of cranberry extract is lacking. (4)


There is a good chance that your cat’s bladder infection can be cured with an accurate diagnosis and the right antibiotic. 

In some cases, the infection can come back, especially if the treatment did not last long enough. Resistant microbes and ongoing underlying diseases increase the risk of chronic and recurrent UTIs in cats. 

Home Care

Some of the things people have tried include cranberry supplements, increasing water intake, and improving litterbox hygiene. Unfortunately, there is not enough evidence to recommend any particular product or strategy to prevent feline UTIs. 

Treatment of underlying diseases such as kidney insufficiency, diabetes, hyperthyroidism, urinary incontinence and bladder stones may lower your cat’s risk of getting a UTI.

When should my cat see a veterinarian?

Your cat should see a veterinarian as soon as you notice any symptoms of lower urinary tract trouble (see list of symptoms above). If your cat shows lethargy, vomiting, inability to pass urine or trouble breathing, consider it an emergency situation. 

What questions should I ask the veterinarian?

  • Does my cat have a bacterial infection?
  • Does my cat have a blocked urethra?
  • Is my cat suffering from an underlying disease?
  • When does my cat need to be rechecked?

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Related Posts


  1. Dorsch, R., Teichmann-Knorrn, S., & Sjetne Lund, H. (2019). Urinary tract infection and subclinical bacteriuria in cats: a clinical update. Journal of feline medicine and surgery, 21(11), 1023-1038.
  2. Martinez-Ruzafa, I., Kruger, J. M., Miller, R., Swenson, C. L., Bolin, C. A., & Kaneene, J. B. (2012). Clinical features and risk factors for development of urinary tract infections in cats. Journal of feline medicine and surgery, 14(10), 729-740.
  3. Mayer-Roenne, B., Goldstein, R. E., & Erb, H. N. (2007). Urinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease. Journal of feline medicine and surgery, 9(2), 124-132.
  4. Weese, J. S., Blondeau, J. M., Boothe, D. M., Guardabassi, L., Gumley, N., Papich, M. G., Jessen, L. R., Lappin, M. R., Rankin, S. C., Westropp, J. L., & Sykes, J. E. (2019). International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Veterinary Journal, 247, 8–25.