Urinary Tract Infections in Dogs and Cats

What is a UTI?

A urinary tract infection (UTI) refers to a bacterial infection or inflammation of any or all parts of the urinary tract, but it most commonly involves the urinary bladder (bacterial cystitis). Older female dogs (ages 7 and up), as well as those with diabetes mellitus or bladder stones are more prone to develop UTIs than the general population.

Cat urinary tract infections are rare compared to the occurrence of UTIs in dogs; however, older cats often experience a host of other urinary tract issues that cause similar symptoms. Male cats are more prone to urinary diseases since their narrower urethras are more likely to become blocked. Feline Lower Urinary Tract Disease (FLUTD) is a general term referring to a cluster of clinical symptoms. FLUTD can cause issues in your cat’s urethra and bladder, often leading the urethra to become obstructed, preventing your cat's bladder from emptying properly. These conditions can be serious or even life-threatening if left untreated. When cats do develop urinary tract infections it is often a sign that they are suffering from an underlying endocrine disease, such as hyperthyroidism or diabetes mellitus.

What are the causes of a UTI?

Bacteria - Most commonly, a UTI occurs when bacteria (such as E. coli) travel up the urethra and into the bladder. Urine in the bladder is supposed to be sterile, but once bacteria find their way there, they can grow and reproduce, causing a UTI.
Abnormal pH levels – Dogs and cats are carnivores and should be eating a species-appropriate diet high in meat protein and low in starches. For a healthy dog or cat eating such a diet, the pH of the urine will be on the slightly acidic side of neutral (between 6.0 and 7.5). When the urine pH goes below or above this range, crystals and even bladder stones can form.
Dry food/kibble diet - Ultra-processed kibble is higher in carbohydrates and starches. This type of diet will raise pH levels in the urine which will predispose your pet to bacterial infections and crystal formation. Furthermore, many over-the-counter diets are too high in magnesium, ammonium, and phosphate which is what makes up the common struvite crystal.
Congenital abnormalities - Some female puppies can have an inverted vulva, which allows urine to pool in the folds. This makes it easier for bacteria to ascend the urethra and cause an infection in the bladder. If you have a puppy with this issue, it is best to have them go through a heat cycle before spaying them to allow the vulva to fully develop. The hormones will cause the vulva to swell during the heat cycle and can help resolve the problem. Spinal cord issues can also trigger urinary tract problems.
Medications and comorbidities - UTI infections are more common if there are concurrent conditions that lower your dog’s immunity, such as diabetes or Cushing’s Disease. Diabetes can put sugar into the urine and that sugar feeds on bacteria. Immunosuppressive drugs like steroids and Apoquel also lower immunity.
Incontinence due to excessive water consumption, a weak bladder sphincter, early spay, or neurologic damage
Emotional or environmental stressors – more common in cats than dogs
Injury or tumor in the urinary tract

What are the signs and symptoms of a UTI?

Bladder issues stem from inflammation – with or without bad bacteria present. The symptoms listed below do not always mean that a UTI is present, but instead, can signal other diseases. For example, dogs and cats who have bladder stones are also more prone to recurrent UTIs. In more severe, but less common cases, causes of a UTI include cancer, bladder and kidney disease (including stones), diabetes, bladder inflammation or infection, spinal cord abnormalities, and prostate disease. This highlights the importance of getting a complete diagnosis whenever there is evidence of disease in the urinary tract.

Symptoms of UTIs in dogs and cats include:

Wanting to be let outside more frequently
Signs of urgency and frequent urination
Urinating small volumes, dribbling urine, or not urinating when posturing to urinate
A break in housetraining, urinating in inappropriate places (such as outside the litterbox)
Straining while urinating
Crying out or whining while urinating
Dripping urine, or frequent licking of the genitals
Urine with a strong odor
Cloudy or bloody urine
Fever, abdominal pain, inappetence, lethargy, and vomiting

How is a UTI diagnosed?

If any of the above symptoms are observed in your pet, it’s important to take them to the veterinarian for a check-up. Your veterinarian will first do a physical examination to make sure there are no congenital problems that are predisposing them to factors that could be leading to an infection. The doctor will also perform a urinalysis using a sterile urine sample from your dog or cat. Pet parents can collect a “free catch” sample of urine, or the veterinarian can obtain a free-catch sample in the office. If your pet cannot provide a urine sample on their own, veterinarians can use a procedure called cystocentesis, during which a needle is inserted through the body wall into the bladder and urine is removed by a syringe. This technique is very safe and mostly painless to your pet.

The urinalysis can reveal important information when a UTI is suspected. Your veterinarian will look at the following:

Urine-specific gravity (how well the animal is concentrating their urine)
pH (certain pH levels can indicate infection or other problems)
Crystals (can be related to stone formation)
Ketones (sometimes seen in cases of diabetes or body-wasting)
Glucose (sugar in the urine, usually a sign of diabetes)
Bilirubin (a breakdown product of blood)
Blood (can indicate infection, hemorrhage, or a breakdown of red blood cells)
Protein (can be a sign kidney disease, infection, and/or Cushing’s Disease)
Leukocytes (white blood cells associated with inflammation, infection, trauma, or cancer)
Bacteria (sign of infection or a contaminated sample)

Test strips are available for home use as a screening test if you suspect your pet may have a urinary tract infection.

If the urinalysis confirms a bacterial infection, your veterinarian should recommend running a urine culture. This will help identify what type of bacteria is present and which antibiotic will work against it. Once the culture and sensitivity results are received, an appropriate antibiotic will be prescribed. It is important to finish the entire course of the antibiotic, even if symptoms disappear before all the medication is used. About two weeks after the last dose of medication, it is important to recheck the urinalysis to confirm that the infection is resolved.

A note on antibiotics: UTI’s can occur for several reasons, with bacterial infections being one. If test results show signs of inflammation but no bacteria are present, an antibiotic should not be given. Antibiotics are standard treatment for UTIs; however, the problem with this is that antibiotics don’t just kill the bacteria causing the UTI … they also destroy the healthy bacteria in your dog’s gut. Using antibiotics will damage your pet’s microbiome. Therefore, it is important to use antibiotics as a treatment for a UTI only when test results show that bacteria are present and are the cause of the inflammation.

How can I support my pet during and after a UTI?

Feed fresh, less processed food – Kick the kibble to the curb! There are many reasons why I don’t recommend a kibble diet, but urinary and kidney problems are at the top of the list. A species appropriate diet, high in protein and low in starch, whether it is commercial or home cooked, is recommended. At the very least, switch to a high-quality canned food.
Keep your pet hydrated - Provide lots of fresh water, preferably filtered, to keep the urine diluted.
Probiotics - Probiotic supplementation adds "good bacteria" to your pet's gut microbiome and is a powerful tool for fighting and preventing UTIs. Probiotics also help restore and maintain a healthy balance of diverse types of bacteria in your pet's body, especially while he/she is taking antibiotics. Good bacterial balance gives bad bacteria less of an opportunity to survive, grow, and potentially cause infection.
Monitor your pet’s urine pH – Use urine test strips to check your dog’s urine first thing in the morning, prior to feeding. Keep a journal of the results and you’ll be able to get a good idea of where your dog’s pH is. Then you can adjust their diet and supplements as needed.
Herbs, Vitamins and Supplements – There are a host of herbs, vitamins and supplements you can use to reduce inflammation and infection and maintain a healthy urinary tract.

D-Mannose stops E coli from attaching to the urinary tract and is shown to work better than some antibiotics.
Cranberries are a well-known remedy for UTIs in humans; they also work for dogs and cats as well. Do not use cranberry juice but instead use fresh or frozen crushed cranberries or a cranberry supplement.
Parsley leaf is a diuretic with antiseptic properties.
Methionine is an amino acid that helps chelate heavy metals and regulates the formation of ammonia. Methionine is helpful in lowering urine pH.
N-Acetyl-Glucosamine (NAG) is a derivative of glucose and comes from the outer shell of crustaceans. NAG is found to target mucous membranes like the GI tract and the bladder, which can help protect it from irritations like urinary crystals.
Juniper berry helps the body flush out uric acid and excess crystals.
Marshmallow root soothes inflamed tissues and protects tissues while passing stones
Uva ursi eases swelling of the bladder and urinary tract.
Couch grass is anti-inflammatory, mild antimicrobial, and pain soother. It is also a diuretic, which means it can help encourage waste elimination.
Corn silk is a natural diuretic which helps naturally eliminate excess water from the body. Corn silk also contains natural polysaccharides to help ease pain and inflammation, which are common symptoms and side effects of a dog with a UTI infection.
Horsetail is antimicrobial; it is best used in combination with marshmallow root.
TCVM (Traditional Chinese Veterinary Medicine) – herbal formulas such as Ba Zheng San and Zhu Ling San promote urination, clear heat, nourish Yin, and unblock painful urinary dysfunction. Consult with a TCVM veterinarian to determine the best formula for your pet.