Urinary tract infection (UTI)

Alternative Names:

Bladder infection; UTI; Cystitis bacterial; Pyelonephritis; Kidney infection

What is a urinary tract infection?

A urinary tract infection is a very common type of infection in your urinary system. It can involve any part of your urinary system. Bacteria — especially E. coli — are the most common cause of UTIs. Symptoms include needing to pee often, pain while peeing and pain in your side or lower back. Antibiotics can treat most UTIs.

A urinary tract infection (UTI) is an infection in any part of the urinary system. The urinary system includes the kidneys, ureters, bladder and urethra. Most infections involve the lower urinary tract — the bladder and the urethra.

UTIs are common infections that happen when bacteria, often from the skin or rectum, enter the urethra, and infect the urinary tract. The infections can affect several parts of the urinary tract, but the most common type is a bladder infection (cystitis).

Are women more at risk to have a urinary tract infection (UTI)?

Women are at greater risk of developing a UTI than are men. If an infection is limited to the bladder, it can be painful and annoying. But serious health problems can result if a UTI spreads to the kidneys.

How is a urinary tract infection (UTI) treated?

Healthcare providers often treat urinary tract infections with antibiotics. You can also take steps to lower the chance of getting a UTI in the first place.

Bacteria cause UTIs and antibiotics treat them. However, any time you take antibiotics, they can cause side effects. Side effects can include rash, dizziness, nausea, diarrhea, and yeast infections. More serious side effects can include antibiotic-resistant infections or C. diff infection, which causes diarrhea that can lead to severe colon damage and death. Call your healthcare professional if you develop any side effects while taking your antibiotic.

If your healthcare professional prescribes you antibiotics:

→ Take antibiotics exactly as your healthcare professional tells you.

→ Do not share your antibiotics with others.

→ Do not save antibiotics for later. Talk to your healthcare professional about safely discarding leftover antibiotics.

→ Drink plenty of water or other fluids. Your healthcare professional might also recommend medicine to help lessen the pain or discomfort. 

→ Talk with your healthcare professional if you have any questions about your antibiotics.

The best thing to do for a urinary tract infection is to see a healthcare provider. You need antibiotics to treat a UTI. Your provider will select an antibiotic that works best against the bacteria responsible for your infection.

Once you get a prescription for antibiotics, it’s very important that you follow the directions for taking them. Be sure to take the full course of antibiotics, even if your symptoms go away and you start feeling better. If you don’t finish all your medicine, the infection can return and be more challenging to treat.

If you get UTIs a lot, a provider may recommend that you take antibiotics:

• Every day.
• Every other day.
• After sex.
• At the first sign of symptoms.

What are symptoms of a urinary tract infection (UTI)?

Symptoms may include:

→ A strong urge to urinate that doesn't go away/ Feeling the need to urinate despite having an empty bladder

→ A burning feeling when urinating

→ Urinating often, and passing small amounts of urine

→ Urine that looks cloudy

→ Urine that appears red, bright pink or cola-colored — signs of blood in the urine

→ Strong-smelling urine

→ Pelvic pain, in women — especially in the center of the pelvis and around the area of the pubic bone

→ In older adults, UTIs may be overlooked or mistaken for other conditions.

→ Pressure or cramping in the groin or lower abdomen

Younger children may not be able to tell you about UTI symptoms they are having. While fever is the most common sign of UTI in infants and toddlers, most children with fever do not have a UTI. If you have concerns that your child may have a UTI, talk to a healthcare professional.

Sometimes other illnesses, such as sexually transmitted diseases, have symptoms similar to UTIs. Your healthcare professional can determine if a UTI or different illness is causing your symptoms and determine the best treatment.

What are the causes of a urinary tract infection (UTI)?

UTIs typically occur when bacteria enter the urinary tract through the urethra and begin to spread in the bladder. The urinary system is designed to keep out bacteria. But the defenses sometimes fail. When that happens, bacteria may take hold and grow into a full-blown infection in the urinary tract.

Risk factors for UTIs that are specific to women include:

Female anatomy: 

Women have a shorter urethra than men do. As a result, there's less distance for bacteria to travel to reach the bladder.

Sexual activity: 

Being sexually active tends to lead to more UTIs. Having a new sexual partner also increases risk.

Certain types of birth control: 

Using diaphragms for birth control may increase the risk of UTIs. Using spermicidal agents also can increase risk.

Menopause: 

After menopause, a decline in circulating estrogen causes changes in the urinary tract. The changes can increase the risk of UTIs.

Other risk factors for UTIs include:

Urinary tract problems: 

Babies born with problems with their urinary tracts may have trouble urinating. Urine can back up in the urethra, which can cause UTIs.

Blockages in the urinary tract: 

Kidney stones or an enlarged prostate can trap urine in the bladder. As a result, the risk of UTIs is higher.

A suppressed immune system: 

Diabetes and other diseases can impair the immune system — the body's defense against germs. This can increase the risk of UTIs.

Catheter use: 

People who can't urinate on their own often must use a tube, called a catheter, to urinate. Using a catheter increases the risk of UTIs. Catheters may be used by people who are in the hospital. They may also be used by people who have neurological problems that make it difficult to control urination or who are paralyzed.

A recent urinary procedure: 

Urinary surgery or an exam of your urinary tract that involves medical instruments can both increase the risk of developing a UTI.

Can cold weather cause a UTI?

Cold weather can indeed have an impact on the incidence of urinary tract infections (UTIs) in women. Some studies have suggested a link between UTIs and cold weather, often as a result of cold-induced diuresis (a condition in which the kidneys filter too much bodily fluid). This is a physiological response where the body attempts to prevent hypothermia by decreasing blood flow to the skin and concentrating it around vital organs, which can exacerbate issues like residual urine, urge incontinence, and excessive nighttime urination. Interestingly, contrasting evidence shows that warmer weather may actually increase the risk for UTIs. Research indicates that on days when the temperature was between 25 and 30°C, the incidence of UTIs in women treated in outpatient settings was increased by 20–30% compared to days when the temperature was cooler, between 5 and 7.5°C. UTIs are among the most common infections in women and can occur at any age, with the highest prevalence in pregnant and postmenopausal women. These infections often accompany vaginal infections and are frequently caused by pathogens from the digestive tract.

It's essential to understand that while environmental factors like weather can influence the prevalence of UTIs, the primary cause is usually the presence of pathogenic bacteria, most commonly E. coli. Preventative measures, such as maintaining proper hygiene, staying hydrated, and dressing appropriately for the weather to avoid excessive cold exposure, can help reduce the risk of UTIs.

What are the different types of UTIs?

Infection of the bladder:

This type of UTI is usually caused by Escherichia coli (E. coli). E. coli is a type of bacteria commonly found in the gastrointestinal (GI) tract. But sometimes other bacteria are the cause. Having sex also may lead to a bladder infection, but you don't have to be sexually active to develop one. All women are at risk of bladder infections because of their anatomy. In women, the urethra is close to the anus. And the urethral opening is close to the bladder. This makes it easier for bacteria around the anus to enter the urethra and to travel to the bladder.

Infection of the urethra: 

This type of UTI can happen when GI bacteria spread from the anus to the urethra. An infection of the urethra can also be caused by sexually transmitted infections. They include herpes, gonorrhea, chlamydia and mycoplasma. This can happen because women's urethras are close to the vagina.

What are possible complications of UTIs?

When treated promptly and properly, lower urinary tract infections rarely lead to complications. But left untreated, UTIs can cause serious health problems.

Complications of a UTI may include:

→ Repeated infections, which means you have two or more UTIs within six months or three or more within a year. Women are especially prone to having repeated infections.

→ Permanent kidney damage from a kidney infection due to an untreated UTI.

→ Delivering a low birth weight or premature infant when a UTI occurs during pregnancy.

→ A narrowed urethra in men from having repeated infections of the urethra.

→ Sepsis, a potentially life-threatening complication of an infection. This is a risk especially if the infection travels up the urinary tract to the kidneys.

How to prevent UTIs?

These steps may help lower the risk of UTIs:

→ Drink plenty of liquids, especially water. Drinking water helps dilute the urine. That leads to urinating more often — allowing bacteria to be flushed from the urinary tract before an infection can begin.

→ Try cranberry juice. Studies that look into whether cranberry juice prevents UTIs aren't final. However, drinking cranberry juice is likely not harmful.

→ Wipe from front to back. Do this after urinating and after a bowel movement. It helps prevent the spread of bacteria from the anus to the vagina and urethra.

→ Empty your bladder soon after having sex. Also drink a full glass of water to help flush bacteria.

→ Avoid potentially irritating feminine products. Using them in the genital area can irritate the urethra. These products include deodorant sprays, douches and powders.

→ Change your birth control method. Diaphragms, unlubricated condoms or condoms treated with spermicide can contribute to bacterial growth.

→ Take showers instead of baths.

→ Teach girls when potty training to wipe front to back.

What tests will be done to diagnose a urinary tract infection?

A healthcare provider may order the following tests to diagnose a UTI:

Urinalysis: 

During this test, you’ll pee into a special cup. The provider will send the sample to a laboratory, where technicians will examine it for signs of a UTI using multiple variables such as nitrites, leukocyte esterase and white blood cells.

Urine culture: 

You’ll pee into a special cup, and lab technicians will test your sample to grow and identify any bacteria that are present. Urine cultures are important because they help your provider determine the most appropriate treatment.

If your infection doesn’t respond to treatment, a provider may order the following tests to examine your urinary tract for a disease or injury:

Ultrasound: 

An ultrasound is an imaging test that helps your provider look at your internal organs. An ultrasound is painless and doesn’t require any preparation.

Computed tomography (CT) scan: 

A CT scan is another imaging test. It’s a type of X-ray that takes cross-section images of your body — like slices — that create 3D images of the inside of your body. A CT scan is more precise than a standard X-ray.

Cystoscopy: 

A cystoscopy uses a cystoscope to look inside your bladder through your urethra. A cystoscope is a thin instrument with a lens and a light at the end.

If you get UTIs frequently, a healthcare provider may perform tests to check for other health issues — such as diabetes or an abnormal urinary system — that may contribute to your infections.