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Urinary Tract Infections (UTIs) in Dogs

Urinary tract infections (UTIs) in dogs, especially females, are fairly common compared to cats. UTIs occur when bacteria travel up the urethra into the bladder from the outside environment, causing infection and inflammation (bacterial cystitis). If left untreated, bacteria can travel further upwards and cause infection in the kidneys (pyelonephritis). UTIs may also predispose certain bladder stones to develop concurrently given the change in the urine environment (such as urine concentration, urine pH).

What are the clinical signs of a UTI in dogs?

  • Increase urination frequency (pollakiuria)
  • Blood in the urine (haematuria)
  • Straining when urinating (stranguria)
  • Pain or crying when urinating (dysuria)
  • Urinary incontinence or dripping urine
  • Strong-smelling/odorous urine
  • Excessive licking of the genital area
  • Urinating indoors despite being consistently well house-trained

How is a UTI diagnosed in dogs?
The most important diagnostic test to assess for UTIs in dogs is to perform a urine test (or urinalysis). This involves measuring the urine concentration, a chemical evaluation with a urine test strip (to assess urine pH, presence of red blood cells, white blood cells, protein, glucose, etc.) and a microscopic sediment examination (to assess for cells, crystals, microorganisms, etc.). If there is a high suspicion of a bacterial UTI, a urine sample may be submitted to an external laboratory for urine bacterial culture and sensitivity to identify the exact bacteria causing the infection and the appropriate antibiotic to treat it with. The most accurate urine sample for a bacterial culture and sensitivity is one collected via a very fine needle directly from the bladder (a procedure called cystocentesis) as this avoids contamination of the urine with bacteria from elsewhere outside of the bladder (such as bacteria on the skin near the vulva or environmental contamination).

If the urine test (or urinalysis) also identifies other concurrent abnormalities (e.g. increased crystals, increased cells), abdominal imaging and a blood test may also be recommended as well.

How is a UTI treated in dogs?
Antibiotics: Not all UTIs are the same and the type of antibiotic treatment is often dependent on the type of bacteria involved. The only way to identify which specific bacteria is causing the UTI is to perform a urine bacterial culture and sensitivity test. The laboratory will then also identify which antibiotics are suitable to clear the infection which is important as there is increasing antibiotic resistance with certain bacteria. With first-time UTI occurrences, the veterinarian may prescribe empirical antibiotics (the most commonly used one to treat most UTIs) to provide immediate relief. Once urine culture and sensitivity results return, the antibiotic may need to be changed to a more appropriate option if the initial treatment choice was not as ideal. There is increasing evidence to show that short courses (3 to 5 days) of antibiotics are sufficient to clear sporadic non-complicated UTIs. Once an antibiotic course has been completed, it is important to repeat urine testing to confirm resolution of the UTI.

Pain relief: Pain medication may also be prescribed to provide relief as UTIs can be quite uncomfortable or painful with the bladder wall becoming irritated and inflammed.

Long-term management (e.g. prescription diets, supplements): Dogs with recurrent history of UTIs may require additional long-term management such as prescription urinary diets and supplements like Cystopro which contain antioxidants devised from cranberries to help reduce the risk of bacterial UTIs. Further investigation is likely required to investigate underlying conditions predisposing your dog to a persistent or recurrent UTI.

Why does my dog keep having recurrent or relapsing UTIs?
For dogs with recurrent UTIs (3 or more infections within a 12 month period) or relapsing UTIs (the same bacterial UTI within a 6 month period), a urine bacterial culture and sensitivity test is necessary to ensure the appropriate antibiotic is chosen to avoid increased antibiotic resistance.

Some conditions can increase a dog’s risk of developing UTIs such as:

  • Structural or functional abnormalities
    • Recessed or hooded vulva where the vulva is not completely visible as it is covered by overlying skin folds. These skin folds create a pocketing for moisture, debris and bacteria to accumulate and potentially travel up the urethra to cause a UTI. A surgery, called a vulvoplasty, may be recommended.
    • Incomplete bladder emptying or urinary retention
    • Urinary incontinence (e.g. pelvic bladder)
    • Faecal incontinence
  • Bladder stones
  • Bladder masses or tumours or polyps
  • Reduced immune function
    • Hyperadrenocorticism or Cushing’s disease
    • Diabetes
    • Immunosuppressive drug use (e.g. steroids, chemotherapy)
  • Inappropriate antibiotic treatment
    • Antibiotic resistance (especially when bacterial urine culture and sensitivity has not been performed)
    • Inadequate course (e.g. unable to give medication, not given for the entire prescribed course)