What are urinary tract infections?

Quick Answer
A urinary tract infection (UTI) is an infection of the bladder, kidneys, urethra, and uterers (which connect the bladder to the kidneys). A UTI may be limited to one area of these organs or may spread throughout the urinary tract.
Expert Answers
enotes eNotes educator| Certified Educator

A urinary tract infection (UTI) is an infection of the bladder, kidneys, urethra, and uterers (which connect the bladder to the kidneys). A UTI may be limited to one area of these organs or may spread throughout the urinary tract.


The urinary tract normally contains no microorganisms. However, sometimes bacteria or yeast from the lower gastrointestinal tract or rectal area enter the urinary tract, usually through the urethra (the tube that allows urine to pass from the bladder). A UTI is caused when these harmful organisms affect the urinary tract.

Risk Factors

It is possible to develop a UTI with or without the following risk factors:

Sexual activity. Frequent sexual intercourse increases the risk of UTI. Having unprotected sex raises the risk still further.

Medical conditions. The following medical conditions increase the chance of UTI: urinary tract anatomical defects, vesicoureteral reflux (in which urine washes back up the ureter into the kidneys), diabetes, weakened immune system, kidney stones, enlarged prostate gland, paraplegia or quadriplegia (body paralysis), history of kidney transplant, sickle cell anemia, menopause, and nervous system disorders that make it difficult to completely empty the bladder.

Medical devices and procedures. For females, the following devices and procedures increase the chance of UTI: using a diaphragm for birth control; having a partner who uses condoms with spermicidal foam; having a urinary catheter inserted; and having surgery that involves the urinary tract system.

Medications. Taking antibiotics for other conditions can increase the risk of getting a UTI.

Age and gender. The rate of UTI increases with age in both men and women. The risk of infection increases even further after menopause in women and after age fifty years in men. Women have a high rate of UTI throughout their lives because the openings to the urethra and rectum in women are near one another. Also, the urethra is shorter in women than it is in men.

Genetic factors. Researchers are still trying to understand whether certain genetic factors might make someone more prone to UTIs. Studies seem to show that if a mother has a history of multiple UTIs, then her daughter will be more likely to have UTIs too. There also may be some factors related to blood type that increase the risk for infection.


Although it is possible to have a UTI without any symptoms, most people do notice symptoms, including increased frequency of urination; feeling of urgency, burning, or pain while urinating; itching in the genital area; urinating only small amounts at a time; pain over the area (the pubic area or lower abdomen) of the bladder or pain in the lower back; back and flank pain along the sides under the ribs; blood in the urine or on toilet tissue after wiping (after urination in women); cloudy looking urine, possibly signifying visible pus; unpleasant smell to urine; and new onset of incontinence (inability to hold the urine during the day or at night).

Symptoms that suggest that the infection has reached the kidneys, indicating a more serious problem, are fever and chills and severe pain in the lower back.

Children (babies in particular) may have less common symptoms of UTI, such as irritability, difficulty feeding, incontinence, loose stools, diarrhea, nausea, vomiting, and slow weight gain (failure to thrive). Older people may have more vague symptoms of infection, such as fatigue, confusion, loss of appetite, or trouble walking.

Screening and Diagnosis

The purpose of screening is early diagnosis and treatment. Screening tests are usually administered to people without current symptoms, but who may be at high risk for certain diseases or conditions.

A doctor will want to discuss the infected person’s medical history and current symptoms and will perform a physical examination. The patient will be asked to provide a “clean catch” urine specimen by urinating into a sterile specimen cup.

Urine tests include the following:

Urine dip. This test is often performed in a doctor’s office. A dipstick coated with special chemicals is dipped into the patient’s urine sample. Areas on the stick will change color if blood, pus, bacteria, or other materials are present.

Microscopic urinalysis. The urine is examined under a microscope for the presence and quantity of red blood cells, white blood cells (pus), bacteria, and other substances. Microscopic urinalysis is a more accurate way to diagnose a UTI.

Urine culture and sensitivity test. A urine sample is sent to a laboratory to see if bacteria will grow. Once the bacteria have been identified, an appropriate antibiotic can be prescribed.

More extensive testing of the urinary system may be necessary for men or children who develop UTIs. Additionally, the doctor may request further testing if there is a concern that the patient has a structural problem with the urinary tract system, or has other conditions, such as urinary stones, vesicoureteral reflux, enlarged prostate, tumors, or polyps. Such further tests includes kidney-ureter-bladder X ray, intravenouspyelogram, kidney ultrasound, spiral computed tomography scan, voiding cystourethrogram, nuclear cystogram, and cystoscopy.

There is no consensus as to whether healthy people should be screened for UTIs. It is common practice to regularly screen pregnant girls and women in their first trimester of pregnancy. Some doctors also screen for UTIs in persons with diabetes.

Urine dip tests and urinalysis are frequently performed as screening tests for conditions other than UTIs (such as in well-child check-ups and other routine adult physical examinations). In the process of using these tests to screen for other conditions, asymptomatic UTIs may be diagnosed. However, these infections do not always need to be treated. Treatment is sometimes recommended and is often not required.

Treatment and Therapy

Urinary tract infections are primarily treated with antibiotic medications. The goals of treatment are to eliminate the bacteria causing the infection and to relieve the discomfort. Treatment involves lifestyle changes, medications, and alternative and complementary treatments. Surgery is generally not considered for treatment.

As of 2015, however, concerns had grown among scientists and health professionals that more cases have been occurring over the years in which UTIs are caused by Escherichia coli (E. coli) bacteria that has become resistant to the antibiotics typically administered as treatment. As the majority of UTIs are caused by the E. coli bacteria, this discovery has prompted researchers to look into the potential source of the resistant bacteria (with some arguing that it largely originates in poultry treated with antibiotics) as well as alternative treatments for infections. A study published in the journal PLOS Pathogens in early 2015 discussed the possibility of using an experimental drug to boost the body's immune system to produce more antimicrobials.

Prevention and Outcomes

There are a number of recommendations that may help a person prevent UTIs. Persons who have frequent UTIs may be helped by taking a small daily dose of an antibiotic or by taking cranberry tablets. Persons who tend to get an infection after sexual intercourse might be advised to take a dose of antibiotic just before or just after engaging in intercourse. Both trimethoprim-sulfamethoxazole and nitrofurantoin are used in small doses to prevent UTIs. Cranberry extract has been shown to be of similar efficacy with lower side effects.

Other ways to reduce the risk of UTI include drinking increased amounts of water (several eight-ounce glasses each day), which may help flush out the urinary system and wash out bacteria, or drinking cranberry juice too. Some studies have suggested that one to three cups per day makes the urine more acidic, which can help prevent the growth of bacteria.

It is possible that sitting in bath water (especially soapy bath water) may irritate skin tissue and make a person more susceptible to infection. Furthermore, using perfumed products, bubble bath, douches, or feminine hygiene sprays may also increase the risk of developing a UTI.

Women should carefully wipe themselves after urinating or after a bowel movement, from the labia (the front) to the rectum (the rear). This avoids contamination of the urethral or vaginal areas with bacteria from the rectum.

One should avoid holding one’s urine for extended periods of time, should ensure that the bladder is emptied completely when urinating, and should urinate before and after sexual intercourse. Also, drinking an eight-ounce glass of water can help flush out bacteria that may have entered the urethra during intercourse.

Finally, one should wear cotton underwear, which is more absorbent than underwear made with artificial fibers. Cotton also wicks moisture from the skin. Artificial fibers, such as nylon and polyester, trap moisture, making an ideal growing environment for bacteria (and yeast), which can promote infections.


Alexander, Ivy L., ed. Urinary Tract and Kidney Diseases and Disorders Sourcebook: Basic Consumer Health Information about the Urinary System. 2nd ed. Detroit: Omnigraphics, 2005. Print.

Boston Women’s Health Collective. Our Bodies, Ourselves: A New Edition for a New Era. New York: Simon, 2005. Print.

Gorbach, Sherwood L., John G. Bartlett, and Neil R. Blacklow, eds. Infectious Diseases. 3rd ed. Philadelphia: Saunders, 2004. Print.

McKenna, Maryn. "How Your Chicken Dinner Is Creating a Drug-Resistant Superbug." Atlantic. Atlantic Monthly Group, 11 July 2012. Web. 30 Dec. 2015.

McMurdo, M. E., et al. “Cranberry or Trimethoprim for the Prevention of Recurrent Urinary Tract Infections?” Journal of Antimicrobial Chemotherapy 63.2 (2009): 389–95. Print.

Parker, James N., and Philip M. Parker, eds. The Official Patient’s Sourcebook on Urinary Tract Infection. San Diego: Icon Health, 2002. Print.

Schrier, Robert W., ed. Diseases of the Kidney and Urinary Tract. 8th ed. Philadelphia: Wolters Kluwer, 2007. Print.

Sifferlin, Alexandra. "This New Drug Might One Day Cure Even the Most Painful UTIs." Time. Time, 30 Apr. 2015. Web. 30 Dec. 2015.