What are Urinary Tract Infections?

Authors: Kyle Gontjes & Karen Jones

Bacteria in Urological Health & Disease

Bacteria serve many roles in the development and maintenance of urological health. Healthy vaginal microbiomes can reduce the risk of preterm birth, promote early childhood immune system development, and facilitate the prevention of urinary tract colonization and infection.

While the urethra is a portal for the exit of urine, it also permits the reverse-entry of bacteria. Fortunately, bacterial colonization of the urinary tract without any symptoms doesn't indicate an infection that needs to be treated, as bacteria are typically harmless or beneficial. Symptomatic urinary tract infection occurs when microorganisms, predominantly bacteria, disrupt the healthy urinary tract and cause infection-related symptoms such as fever, suprapubic pain, and urinary frequency.

Urinary tract infection, often abbreviated as UTI, is one of the most common bacterial infections, annually affecting 150 million people worldwide. In the United States, UTIs annually account for over 10 million acute care visits, 2 million emergency department visits, and a societal cost of over $3 billion dollars.

While UTIs are a common infection, myths and misconceptions continue to persist. In this explainer, and throughout our subsequent educational modules on UTIs, the authors will explain the prevalence and biology of UTIs, current diagnostic and treatment options, and the persistent challenges facing UTI prevention.

Image by Peter Dazeley via Getty Images

What is a Urinary Tract Infection?

Urinary tract infections are infections of the upper or lower urinary tract that are caused by microorganisms. Urinary tract infections occur when microorganisms, typically bacteria, enter via the urethra and colonize the urinary tract. While asymptomatic bacteriuria is common, sometimes microorganisms can disrupt the healthy urinary tract, causing UTI-related symptoms. The majority of UTIs are located in the lower urinary tract due to the bladder and urethra's close proximity to extragenital microorganisms.  

Urinary tract infection degree of severity and clinical presentation varies on a case-by-case basis. The majority of uncomplicated UTI cases are mild and self-limiting, meaning that your body can fight off the infection without treatment.

Common UTI symptoms include: 

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Who is at risk for Urinary Tract Infections? 

Urinary tract infections are most common in women, the elderly, those who engage in frequent sexual intercourse, users of certain birth control methods (spermicidal, diaphragm, and unlubricated condoms), those with urinary incontinence and the presence of an indwelling urinary catheter, oftentimes called "Foley" catheters. Patients who are of advanced age, are immunocompromised, or have chronic "Foley" catheters, are at a greater risk for complications associated with UTIs.

Patients with a history of UTIs are at a greater risk for recurrent or chronic UTIs. Bacteria can persist within the urinary tract, become undetectable, and when advantageous, can disrupt the urinary tract, causing UTI symptoms. 

Approximately two-thirds of UTI cases are women. By the age of 35, almost half of all women will get at least 1 UTI. The hormonal changes that occur during pregnancy and menopause alter the vaginal bacterial community and increase susceptibility to UTIs. 

How are Urinary Tract Infections Diagnosed? 

Before diagnostic testing, physicians use the patient's history and clinical presentations to determine the necessity for urine analysis and subsequent culturing. To minimize inappropriate testing, physicians look for UTI-related clinical indications before ordering diagnostic tests. 

After determining the necessity to test for UTIs, physicians typically order a urinalysis (UA). Urinalysis yields the biochemical profile of the urine, looking for the presence of red or white blood cells, and other urine properties like glucose, protein and leukocyte concentrations. Urinalysis results alone aren't conducive for the diagnosis and treatment of UTIs.

If the UA results cause physicians to suspect a UTI, a urine culture will be ordered. Urine cultures test to identify the presence of microorganisms, what type(s) of microorganisms are present, and their susceptibility to antimicrobials. Positive urine cultures alone aren't conducive for the diagnosis and treatment of UTIs. 

The physicians will review the patient history, clinical presentation, and Urinalysis/Urine Culture results to diagnose a UTI and determine the necessity for antibiotic therapy.

Image by Federico Candoni via Wiki Commons

How are Urinary Tract Infections Treated?

For patients requiring curative treatment, a physician will order a course of antibiotic therapy. Antibiotic regimens are typically short in duration (1-7 days). Longer courses of antibiotics may be required for diabetics, pregnant women, and those with complicated UTIs. Physicians may prescribe Phenazopyridine (Pyridium®), an analgesic that can alleviate urinary pain and discomfort.

Common medications used to treat uncomplicated UTI are Nitrofurantoin or Trimethoprim/sulfamethoxazole (TMP/SMX). For an extensive list of treatment regimens, refer to the Michigan Hospital Medicine Safety Consortium’s Guidelines for Treatment of Urinary Tract Infections and their convenient UTI Pocket Cards

As antibiotic resistance is a growing clinical challenge, the most appropriate antibiotic regimen will be determined by the causative microorganism’s susceptibility to antibiotics.

How Can I Prevent Myself from Getting Urinary Tract Infections?

There are plenty of ways for you to reduce your risk of acquiring a UTI:

Current Challenges to Urinary Tract Infection Management & Prevention:

Clinical research groups, including our own, work to identify and promote clinical interventions for the treatment, management, and prevention of UTIs. Current challenges include: 

Why is it Important to Understand Urinary Tract Infections?

Urinary tract infections are common infections that are becoming harder to treat due to antibiotic resistance. Understanding the causes, risk factors, diagnostic procedures and treatment options of UTIs, is crucial for the provision of excellent health care. Familiarization with the clinical presentations and risk factors associated with UTIs will equip healthcare workers to effectively combat UTI myths and misconceptions, providing reassurance to patients and their family members.