Men get urinary tract infections when bacteria enter the urethra and travel into the bladder or beyond. This is relatively rare in younger men, with only about 5 to 8 cases per 10,000 men under age 50 each year. But the risk climbs significantly with age, mostly because of prostate changes, catheter use, and other factors that make it harder to fully empty the bladder. Understanding the specific pathways bacteria use to get in helps explain why certain men are more vulnerable than others.
Why Men Get Fewer UTIs Than Women
The male urethra is about 18 to 20 cm long, roughly four to five times the length of the female urethra. That extra distance acts as a physical barrier: bacteria that enter the opening of the urethra have a much longer journey before they can reach the bladder. Along the way, glands lining the urethra secrete mucus that helps protect the underlying cells and flush out potential invaders. This built-in defense system is the main reason that fewer than 0.1% of young men carry bacteria in their urine at any given time.
But length alone isn’t a guarantee. When something disrupts the normal flow of urine or introduces bacteria directly into the urinary tract, those defenses can be bypassed entirely.
An Enlarged Prostate Is the Most Common Culprit
The prostate gland sits just beneath the bladder, and the urethra passes directly through its center. As men age, the prostate often grows larger, a condition called benign prostatic hyperplasia (BPH). When this happens, the expanding tissue squeezes the urethra and starts to block urine flow. The result is a bladder that never fully empties.
That leftover urine is the problem. Stagnant urine sitting in the bladder creates a warm, nutrient-rich environment where bacteria thrive. Instead of being flushed out with each trip to the bathroom, bacteria accumulate and multiply. This is why UTI rates in men rise sharply after age 50, right when prostate enlargement becomes common. Symptoms of BPH itself, like difficulty starting to urinate, a weak stream, or feeling like you still need to go after finishing, often overlap with early UTI symptoms, which can delay diagnosis.
Catheters and Medical Procedures
Urinary catheters are one of the most direct ways bacteria enter the urinary tract. A catheter is a thin tube inserted through the urethra into the bladder to drain urine, typically used during surgery, hospitalization, or for men who can’t urinate on their own. The tube creates a direct path for bacteria to travel from outside the body into the bladder, completely bypassing the urethra’s natural defenses.
The risk of infection increases the longer the catheter stays in place. Catheter-associated UTIs (CAUTIs) are among the most common hospital-acquired infections. Even with sterile insertion techniques, bacteria can migrate along the surface of the catheter or enter during routine care. Any man who has had a catheter, even briefly after a surgical procedure, has an elevated risk of developing a UTI in the days that follow.
Sexual Activity and STI-Related Infections
Sex can introduce bacteria into the urethra, particularly during anal intercourse, where exposure to intestinal bacteria is more likely. Men who have sex with men face a higher risk for this reason, though any sexual activity can potentially push bacteria toward the urethral opening.
It’s also worth distinguishing a UTI from urethritis, which is inflammation of the urethra often caused by sexually transmitted infections like chlamydia or gonorrhea. The symptoms can look similar: burning during urination, urgency, and discomfort. But urethritis from an STI often includes discharge from the tip of the penis, which can be cloudy, yellow, white, or blood-tinged. A standard UTI rarely causes this kind of visible discharge. Because the overlap in symptoms is significant, testing for both conditions is common when a man shows up with urinary pain.
Other Risk Factors That Open the Door
Several other conditions make UTIs more likely in men:
- Kidney stones: Stones can partially block the urinary tract, trapping urine and giving bacteria a surface to cling to. Even small stones that don’t cause pain can increase infection risk.
- Diabetes: Elevated blood sugar impairs the immune system’s ability to fight off bacterial infections, and sugar in the urine itself can feed bacterial growth.
- Weakened immune system: Conditions or medications that suppress immune function, including organ transplant drugs and chemotherapy, reduce the body’s ability to clear bacteria from the urinary tract.
- Urinary tract abnormalities: Structural problems present from birth, or scarring from previous infections or surgeries, can prevent normal urine flow and create pockets where bacteria collect.
- Incomplete bladder emptying: Beyond BPH, neurological conditions like spinal cord injuries, multiple sclerosis, or nerve damage from diabetes can prevent the bladder from contracting fully, leaving residual urine behind.
Recognizing Symptoms in Men
UTI symptoms in men are similar to those in women but can sometimes be subtler, especially in older men. The hallmark signs include a strong, persistent urge to urinate, burning or pain during urination, and urine that looks cloudy or has an unusually strong smell. You may also notice you’re urinating more frequently but only passing small amounts each time.
Blood in the urine is another possible sign. It can make urine appear pink, red, or cola-colored, and it takes only a small amount of blood to change the color noticeably. The bleeding itself usually isn’t painful unless blood clots are being passed.
When the infection moves beyond the bladder to the kidneys, symptoms escalate. Fever, chills, nausea, and pain in the back, side, or groin suggest the infection has spread. In men, a UTI can also reach the prostate, causing deep pelvic pain, painful ejaculation, and difficulty urinating. Prostate involvement tends to make the infection harder to clear and more likely to recur.
Why Male UTIs Are Taken Seriously
Medical guidelines often classify UTIs in men as “complicated” by default. This doesn’t necessarily mean the infection is severe. It means that when a man develops a UTI, there’s a higher likelihood that an underlying structural or functional problem is contributing, whether that’s an enlarged prostate, a kidney stone, or incomplete bladder emptying. For this reason, a first-time UTI in a man typically prompts more investigation than one in a woman, including imaging or a referral to a urologist.
The concern about leaving a UTI untreated is real. Bacteria that start in the bladder can travel upward to the kidneys and eventually enter the bloodstream, a condition called urosepsis. Urosepsis can lead to organ damage, organ failure, and septic shock. When caught early, about 70% of people with sepsis survive with treatment, but the condition deteriorates quickly without it. This is why new urinary symptoms in men, especially fever combined with urinary pain, warrant prompt medical attention rather than a wait-and-see approach.