When to see a vet urgently
Contact an emergency vet immediately if your cat has any of these signs:
- repeated straining but passing no urine or only drops;
- severe pain and constant unsuccessful litter tray visits;
- vomiting, staggering or severe tiredness alongside difficulty urinating;
- clearly worsening general health, not eating and possible signs of kidney pain or fever.
A urethral blockage needs to be ruled out quickly, particularly in a male cat. You can find a vet near you.
Overview
In healthy cats, the bladder and urine are sterile, and the lining and immune system protect against infection. When these defences weaken, bacteria, most often Escherichia coli, can enter the urinary tract and cause inflammation. A UTI may be acute or chronic, particularly with untreated kidney disease or diabetes.
Describing urine as sterile is a traditional clinical simplification. New molecular methods have investigated small amounts of bacterial material in healthy cats' urine too, but results and their significance remain partly conflicting. Detecting bacterial DNA alone does not prove disease caused by living bacteria.
Clinical practice distinguishes symptomatic infection from subclinical bacteriuria, meaning bacterial growth in urine without signs of infection. The latter does not usually need antibiotics. Contamination during collection can also explain bacteria in a sample, so the collection method and cat's symptoms affect interpretation.
Causes
The main causes of urinary tract infections in cats include:
- bacteria entering the urethra and bladder from the area around the anus
- diabetes, with glucose in urine encouraging bacterial multiplication
- chronic kidney disease, or CKD
- urinary stones and conditions involving crystal formation
- anatomical abnormalities of the urethra
- a weakened immune system
Infection usually develops when bacteria from the cat's own genital or faecal area ascend the urinary tract and the body's defences cannot stop them. Bladder emptying, lining function and urine properties contribute to protection. A stone or anatomical change may maintain the problem even if bacteria are temporarily cleared by treatment.
An underlying condition does not automatically mean there is a urinary infection. A cat with kidney disease or diabetes may also have asymptomatic bacteriuria, for example. Treatment decisions are based on the overall picture, and control of the underlying disease is assessed at the same time.
Risk factors
UTIs occur more often in cats that are:
- older
- diabetic or affected by CKD
- previously catheterised
- female, with a shorter urethra
- overweight and inactive
Associations between bacterial findings and age, female sex, catheterisation and certain underlying diseases are recognised. Less is known in cats about the independent importance of excess weight and inactivity specifically for bacterial infection than for lower urinary tract symptoms generally. A young cat's bladder symptoms are often more likely to have a cause other than bacteria.
Main symptoms
Clinical signs of a UTI in cats include:
- frequent, painful urination
- blood in the urine, or haematuria
- cloudy or foul-smelling urine
- loud meowing while urinating
- licking the genital area
- urinating outside the litter tray
- tiredness and reduced appetite
⚠️ UTI symptoms resemble cystitis and urinary stone disease, so accurate diagnosis is important.
Cloudiness, smell or blood alone do not establish a bacterial infection. Painful urination can also result from idiopathic cystitis, stones or a blockage. FLUTD is a collective term for these lower urinary tract diseases, rather than a single diagnosis. A previous bacterial infection does not guarantee that the next episode is the same kind of infection.
You may mistake straining in the litter tray for constipation. Check whether urine is being passed and the size of the clumps. If no urine appears, do not stay at home trying more water or a dietary change. Do not squeeze the bladder by hand.
Complications and consequences
Without treatment, a urinary tract infection can lead to:
- chronic cystitis
- pyelonephritis, a kidney infection
- bladder tissue damage
- sepsis, with bacteria spreading into the bloodstream
Not every symptomatic bladder infection progresses to the kidneys or sepsis. However, bacterial inflammation of the renal pelvis and kidney tissue, or pyelonephritis, is a serious possible complication. It may involve vomiting, not eating and declining kidney function. Not every cat has fever or abdominal pain, so their absence does not rule it out.
Diagnosis at the vet
Diagnosis is based on:
- urinalysis for white blood cells, bacteria, blood and pH changes
- urine culture and antibiotic sensitivity testing, the gold standard
- ultrasound of the bladder and kidneys
- blood tests to rule out concurrent disease
What kind of urine sample is needed?
Urine specific gravity indicates concentration. Cells, bacteria and crystals are examined under a microscope, but a pH change, for example, does not alone confirm infection. The white blood cell pad on a human urine dipstick is not a reliable way to diagnose a feline UTI. Tests complement each other.
For culture, a sample is often collected by cystocentesis: inserting a needle through the abdominal wall directly into the bladder. This reduces contamination from external bacteria. A home-collected sample may suit some tests, but culture results are interpreted according to collection method. Ask the practice for instructions before collecting a sample.
Where the patient's condition allows, sampling is attempted before antibiotics start. Mention every medicine already given, as these may affect bacterial growth and result interpretation. However, treatment of a seriously ill cat is not delayed simply while waiting for a perfect sample.
What do culture and ultrasound establish?
Culture determines whether bacteria grow in the sample and which species they are. Sensitivity testing helps choose an effective antibiotic. A positive result is considered alongside symptoms: even a carefully collected sample does not alone distinguish symptomatic infection from asymptomatic bacteriuria.
Ultrasound and, where needed, X-rays look for stones, structural changes or a tumour, for example. Blood tests assess kidney function, diabetes and general condition. With recurrent symptoms, identifying a predisposing factor matters more than simply confirming again that urine contains bacterial growth.
Treatment and recovery
Antibiotics are chosen for a reason
Where possible, medication for a symptomatic bacterial infection is selected according to culture and sensitivity results. If treatment must begin before results, the vet assesses a suitable initial medicine and reviews the choice once results are available. Pain relief may be needed alongside treatment of the infection.
Give medication exactly as instructed. Symptoms stopping is not alone a reason to change treatment, and do not start antibiotics left over from a previous episode yourself. Not every infection needs the same medicine or treatment duration. Kidney infection and recurrent bladder infection are assessed separately.
Catheter-associated risk is not usually prevented by precautionary antibiotics. Aseptic technique and appropriate catheter care are essential. Finding a resistant bacterium in a symptom-free cat's sample does not automatically mean a stronger medicine is needed either.
If symptoms return
If urination does not improve or symptoms recur, contact the practice. The vet assesses whether the same infection persists, a new infection has developed or another urinary tract disease is responsible. A stone, urine remaining in the bladder or a poorly controlled underlying condition may need treatment beyond antibiotics.
The need for follow-up samples is agreed according to the diagnosis and response. Do not extend a course or switch antibiotics yourself if the response is poor. A new examination may identify a cause that longer medication cannot resolve.
Daily life during treatment
Keep clean water readily available and monitor actual urination, appetite and general health. Your cat must be able to reach the litter tray without interference from other cats. A tray with low sides may help an older cat or one with joint pain. A cat in severe pain or straining unsuccessfully needs treatment, rather than prolonged home monitoring.
Prevention
Preventing urinary tract infections in cats involves:
- controlling chronic diseases, including diabetes and CKD
- ensuring free access to water and encouraging drinking
- providing a good-quality diet supporting urinary health
- maintaining a healthy weight
- regular urine testing in older cats
The need for a special diet depends on other urinary disease and the type of any stones. No food marketed generally for urinary health replaces treatment of a confirmed bacterial infection. Evidence in cats for cranberry products, D-mannose and other supplements in preventing recurrent infections is sparse, so do not start them as an antibiotic substitute.
Urine testing intervals are chosen according to symptoms and underlying disease as well as age. With an asymptomatic finding, the vet assesses whether further tests or monitoring are needed. The aim is not to turn every bacterial finding into antibiotic treatment.
Enough litter trays, quiet locations and clean litter your cat likes support regular urination. Poor tray access alone does not establish the cause of an infection, however. If your cat has previous urinary problems, the environment and possible pain are assessed alongside other investigations.
What it means for owners
Urinary tract infections are less common in cats than dogs but always need careful attention. Remember that any change in urination is a reason to consult a vet. Timely urine testing and appropriate antibiotic treatment clear the infection and prevent complications.
Frequently asked questions
Does every bacterial finding in urine need antibiotics?
No. Asymptomatic bacteriuria and sample contamination are distinguished from symptomatic infection. Treatment depends on the cat's condition, collection method and test results. Underlying diseases may also affect the decision.
Can a male cat's difficulty urinating wait until the next day?
No, if no urine or only drops are passed despite repeated straining. Urethral blockage is an emergency and can resemble ordinary bladder symptoms. Seek treatment immediately.
Why does the infection return after antibiotics?
The cause may be a persistent or new infection, a predisposing disease or symptoms unrelated to bacteria. A new sample and, where needed, imaging help distinguish these possibilities. Previous medication is not automatically continued.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- 2025 iCatCare Consensus Guidelines on the Diagnosis and Management of Lower Urinary Tract Diseases in Cats, iCatCare / Journal of Feline Medicine and Surgery, accessed 2026-11-03.
- Bacterial Cystitis in Small Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Pyelonephritis in Small Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Diagnostic Testing, AAFP / AAHA, accessed 2026-11-03.
- Feline Lower Urinary Tract Disease, Cornell Feline Health Centre, accessed 2026-11-03.
- Litter Boxes, Ohio State University Indoor Pet Initiative, accessed 2026-11-03.
- Urinary Tract Infections in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Characterisation and Comparative Analysis of Urinary Bacterial Microbiome Profiling in Healthy Cats and Cats with Feline Idiopathic Cystitis, Scientific Reports, accessed 2026-11-03.