What are the causes of chronic UTIs?

Chronic urinary tract infections (UTIs) occur when a person experiences frequent bacterial infections of the urinary tract, usually two or more infections within six months, or three or more infections in one year.

As with many medical conditions, the causes of chronic UTIs vary greatly. The most common causes of chronic UTIs include:

• Antibiotic-resistant bacteria 
• Decreased estrogen
• Kidney or bladder stones
• Sexual intercourse
• Structural problems in the genital or urinary systems
• Use of incontinence products

These causes can lead to increased risk of chronic UTIs for several different reasons.

Any structural defect that impedes the regular flow of urine can increase the risk of chronic UTIs. For example, kidney stones can block urine flow in the kidneys, ureters (the tube that carries the urine to the bladder from the kidneys) or bladder. Similarly, structural defects in the urinary tract due to congenital malformations, trauma or post-surgical changes can lead to blockages in the urinary system, increasing the risk of recurring bacterial growth.

Your risk for chronic UTIs increases if there is a transfer of genital or anal bacteria into the urinary tract. Unlike the vagina or the anus, the urinary tract is a sterile environment. Bacteria can enter the urinary tract during sexual intercourse, poor hygiene or improper wiping after using the bathroom. More rarely, it can be result from structural connections between organs. While uncommon, trauma, inflammation or frequent infections can create unwanted connections between the urinary tract and the vaginal canal or the gastrointestinal tract. These connections, called fistulas, create internal passages for bacteria that are difficult to diagnose without direct visualization using a scope or contrast-based imaging.

Individuals with medical problems that make it difficult to maintain good hygiene, such as dementia, spinal cord injuries or other mobility limitations, also have an increased risk of UTIs. For example, those who use incontinence products such as pads can get soiled with feces. Urinary catheters (tubes inserted into the urethra and the bladder for the collection of urine) also increase the risk of chronic urinary tract infections, as they may introduce outside bacteria into the urinary tract.

Antibiotic-resistant bacteria can cause recurring UTIs. Repeatedly exposing bacteria to a specific class of antibiotics increases the risk of developing antibacterial resistance, meaning that the bacteria may not be completely killed by the usual class of antibiotics. A UTI that's resistant to the typical antibiotics is more difficult to treat and can lead to complications, including kidney injury, fistula formations and sepsis. Healthcare providers can test for specific susceptibility of the organism in your urine to find the most appropriate medication for each infection.

A decrease in estrogen leads to a higher chance of developing UTIs. This makes menopausal or post-menopausal women more susceptible to developing chronic infections compared to pre-menopausal women.

There are many risk factors for chronic UTIs, including medical, structural and hygienic factors. If you are suffering from chronic UTIs, talk with your healthcare provider to find the potential cause and appropriate treatment.

Published October 2022.