What is a Urinary Tract Infection (UTI)?

A urinary tract infection (UTI) is an infection that affects any part of the urinary system, including the:

  • Bladder (cystitis)
  • Urethra (urethritis)
  • Kidneys (pyelonephritis)
  • Prostate (prostatitis, in men)
  • Epididymis and testicles (epididymo-orchitis, in men)

UTIs are very common, especially in women, babies, and older adults, though men of all ages can also be affected.

What Causes a UTI?

Most UTIs are caused by bacteria entering the urinary tract through the urethra and multiplying in the bladder. The most common cause is E. coli, a bacterium normally found in the bowel. Other microorganisms, including those from sexually transmitted infections (STIs), can also cause UTIs.

Risk Factors for UTIs Include:

  • Being female – women have a shorter urethra, allowing bacteria easier access to the bladder
  • Use of urinary catheters – especially in hospital or after surgery
  • Prostate problems in men – can lead to incomplete bladder emptying
  • Babies – particularly those with urinary tract abnormalities
  • Weakened immune systems – from conditions like cancer or diabetes
  • Unprotected sexual activity – especially with multiple partners

What Are the Symptoms of a UTI?

Symptoms depend on the part of the urinary tract affected.

Bladder or Urethra Infection Symptoms:

  • Burning or pain when urinating
  • Frequent urge to urinate
  • Lower abdominal or pelvic pain
  • Cloudy or foul-smelling urine

Kidney Infection Symptoms (more severe):

  • Fever and chills
  • Back or flank pain
  • Nausea and vomiting
  • Abdominal pain

Kidney infections are serious and require urgent medical attention.

How is a UTI Treated?

UTIs are typically treated with antibiotics. Your doctor may prescribe:

  • Oral antibiotics based on your symptoms and urine test results
  • Intravenous (IV) antibiotics and fluids in hospital if the infection is severe or involves the kidneys

It’s important to complete the full course of antibiotics, even if symptoms improve early.