What is a UTI? Causes, Symptoms, Risk Factors, and How They're Diagnosed.

The Basics

A urinary tract infection (UTI) is an infection that affects part of the urinary system, which is responsible for making, storing, and eliminating urine. Your urinary system includes your kidneys, ureters (tubes connecting the kidneys to the bladder), bladder, and urethra. Most UTIs affect the lower urinary tract — the bladder and urethra. UTIs that affect the upper urinary tract — particularly the kidneys — are less common but can be more serious.

Urinary tract infections are one of the most common infections globally. Each year in the United States, over 8 million doctor visits are attributed to UTIs. Both bacteria and fungi can cause UTIs; however, bacterial UTIs are far more common. The bacteria often originate from the gut and peri-urethral area. However, there are other pathways by which the pathogen can enter the urinary system.

Risk Factors for UTIs

There are many different risk factors for UTIs. Some are related to underlying or co-occurring medical conditions. Others are related to different behaviors. Women are at higher risk than men. Typically, your risk for UTIs increases with age as your immune system changes. Understanding your personal risk factors can help you and your healthcare provider take steps to reduce the chance of future UTIs.

Universal UTI Risk Factors (any sex):

• Prior urinary tract infection
• Recent sexual activity
• Dehydration and infrequent urination
• Constipation
• Recent antibiotic use
• Urinary catheters
• Kidney or bladder stones
• Anatomical or functional urinary tract issues
• Metabolic or immune conditions

Risk Factors in Women:

• Female anatomy
• Contraception using spermicides or diaphragms
• New sexual partners, recent sexual activity, certain sexual practices
• Pregnancy
• Perimenopause and post-menopause
• Pelvic floor dysfunction

Risk Factors in Men:

• Enlarged prostate
• Prostatitis or urethral strictures
• Unprotected anal intercourse

UTI Symptoms

The most common symptom of a UTI is painful urination. You might also experience a more frequent urge to urinate, even when little urine comes out. Urine can become cloudy or smell strong. These symptoms are indicative of a lower urinary tract infection, called cystitis.

Common UTI Symptoms in Cystitis:

• Burning or pain when urinating, called dysuria
• Strong, sudden urge to urinate
• Urinating more often than usual, often in smaller volumes
• Discomfort or pressure in your pelvis
• Cloudy or foul-smelling urine
• Blood in your urine (pink/red/brown tinge)

Fever can accompany UTIs, but it's not always present. When fever occurs with UTI symptoms, it signals the infection may have moved into the upper urinary tract, affecting the kidneys and ureters as well. This type of infection is called pyelonephritis.

Kidney Infection (Pyelonephritis) Symptoms:

• Fever or chills
• Back or flank pain, just below the ribs
• Nausea
• Vomiting
• Feeling generally unwell

Here's what surprises many patients: you can have a UTI with no symptoms at all. This is called asymptomatic bacteriuria—bacteria in your urine without signs of infection. In healthy women, this often doesn't need treatment. In some situations, such as during pregnancy or before certain urologic procedures, treatment may be recommended. In many other cases, asymptomatic bacteriuria does not require treatment.

If you are experiencing UTI symptoms, seek prompt care from your doctor. Your doctor will review your medical history, your symptoms, and order urine tests to determine whether or not you have a UTI. Visiting a doctor is important, as many other conditions can mimic UTI symptoms. Read more about how to talk to your doctor about UTIs.

How Do Doctors Diagnose UTIs?

A UTI is a clinical diagnosis that takes into account a patient's symptoms, medical history, and laboratory findings. To diagnose a UTI, clinicians typically use two main urine tests: urinalysis and urine culture. Urinalysis examines your urine for different chemical signals of infection. These tests are typically very fast. Urine culture involves sending a urine sample to a laboratory. This test attempts to grow the bacteria or fungi causing your UTI, which can take several days. These tests are not always perfect and can be impacted by recent antibiotic use. New diagnostic tests for UTIs are increasingly being used.

One of these newer tests, the BIOTIA-ID Urine Test, uses next-generation sequencing, a technique that looks for pathogen DNA in the urine as opposed to trying to grow any pathogens present. This test is able to identify 40+ urogenital pathogens — including ones that standard urine culture frequently misses — and provides antibiotic resistance information to guide precision treatment.

How are UTIs treated?

Depending on your medical history, current symptoms, and test results, your medical provider will make a decision on how best to treat your UTI. Oftentimes, medical providers will prescribe empiric treatment, meaning they will prescribe you an antibiotic while they wait for test results to come back. Once your doctor knows what is causing your infection, they will then prescribe a drug that works specifically against it.

While empiric treatment is common, it is not always ideal, as unnecessary antibiotic use can contribute to antimicrobial resistance (AMR). This is when bacteria or fungi are no longer able to be killed by the drugs we typically use to treat these infections. Because most UTIs are caused by bacteria, antibiotics are commonly used to treat them. If your UTI is caused by a fungal pathogen, your doctor will prescribe you an antifungal medication. This is why it is important to get tested for your UTI symptoms.