Lower Urinary Tract Infection (Bacterial Cystitis) in Dogs

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Last updated on
5 min read

Key takeaways

Bacterial cystitis is infection and inflammation of the bladder, usually caused by bacteria entering through the urethra in dogs.

  • Bacterial cystitis is commonly called a lower urinary tract infection, or UTI
  • Normally the body clears small amounts of bacteria naturally, but if there is a break in the dog’s immune defenses, pain and inflammation set in
  • This is a very common condition in dogs, especially females
  • Symptoms include frequent urination, straining to urinate, urinating small amounts, and blood in the urine
  • Diagnostic tools include urinalysis, urine culture, and diagnostic imaging
  • The most common treatment is a short course of antibiotics
  • Most cases of bacterial cystitis respond well to treatment and prognosis is good
  • Recurrent infections are commonly associated with underlying diseases that require additional treatment
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A closer look: Lower Urinary Tract Infection (Bacterial Cystitis) in Dogs

The urinary tract has many defenses against bacterial infection that can become disrupted, resulting in infection. These defenses can be weakened by small alterations, such as stress or changes in urinary pH balance, or more severe underlying conditions that impact the immune system or the integrity of the urinary tract lining.

Bacterial cystitis is a very common condition in dogs, especially females. Urinary symptoms are often painful, and warrant timely veterinary attention. Prognosis of acute bacterial cystitis is good with treatment. Recurrent infections are more concerning and can be time-consuming to treat. Treatment of underlying conditions may be required to resolve recurrent UTIs.

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Risk factors

UTIs are common in dogs, especially females. Left untreated, they can lead to more serious urinary tract conditions, some of which can be life threatening. In cases where recurrence is common, further investigation is warranted as long term use of antibiotics can lead to antibiotic resistance, making future infections more challenging to resolve.

Possible causes

Urinary tract infections are caused by bacterial infections in the urinary system that are too severe for the immune system to clear on its own.

In some cases, urinary tract infections affect the urethra as well, resulting in urethritis.

A UTI is considered recurrent if the patient experiences 3 or more infections within 12 months. Factors associated with recurrent UTI include the following:

Decreased kidney function: results in lower than expected concentration of antibiotics in the urine

Low antibiotic absorption: sometimes due to drug compounding or gastrointestinal disease

Inappropriate or poor compliance with antibiotic dose or administration schedule

Main symptoms

Occasionally, animals have bacteria in the urine without symptoms of infection. This condition is called subclinical bacteriuria.

Testing and diagnosis

Diagnosis of bacterial cystitis begins with a physical examination to identify any underlying conditions. Other tests include:

  • Urinalysis
  • Bloodwork
  • Urine culture
  • Diagnostic imaging

Testing for predisposing causes (e.g., bladder stones, nervous system abnormalities, bladder tumors, etc.) is warranted in dogs with recurrent episodes of bacterial urinary tract infection.

Steps to Recovery

Generally, acute infections are treated with a short course of antibiotics.

Treatment of recurring lower urinary tract infections may involve several rounds of urine cultures and longer courses of antibiotics, as well as other therapies to treat any underlying disease.

Acute bacterial cystitis usually resolves after a short course of antibiotic treatment, and the prognosis is good.

In cases of recurrent infection, multiple rounds of antibiotics may be indicated, followed by additional urine cultures. Sometimes this resolves the infection, and other times recurrent episodes persist for life.

Treatment of underlying causes greatly improves prognosis and may stop UTIs entirely. If there are uroliths, surgery may be necessary to remove them, while sometimes the stones dissolve with targeted therapy. Uroliths are frequently recurrent.

Bladder tumors are also commonly associated with recurrent UTIs, and may require chemotherapy, surgical intervention, or radiation therapy. Underlying conditions such as diabetes or Cushing’s disease are treated using medications, and the prognosis is case-dependent.


It is difficult to prevent acute bacterial cystitis in dogs. Providing unlimited access to fresh clean water and frequent opportunities to urinate are recommended. Certain diets may be helpful to dissolve uroliths and/or keep the bladder at the right pH level to prevent bacterial infection from taking hold.

Is Lower Urinary Tract Infection (Bacterial Cystitis) in Dogs common?

Bacterial lower urinary tract infections are very common in dogs, especially females.

Typical Treatment

  • Antibiotics
  • Treatment of underlying conditions
  • Dietary management


Malcolm Weir, DVM, MSc, MPH; Robin Downing, DVM, DAAPM, DACVSMR, CVPP, CRPP - Writing for VCA Animal Hospitals
Dr. Debra Primovic - DVM - Writing for PetPlace
Dr. Bari Spielman - Writing for PetPlace
"JD Foster VMD, DACVIM" - Writing for Today's Veterinary Practice
Scott A. Brown , VMD, PhD, DACVIM - Writing for Merck Veterinary Manual
No Author - Writing for BluePearl Pet Hospital
J Scott Weese - Writing for Royal Canin

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