Urinary tract infections in men are uncommon but not rare. About 12% of men will experience UTI symptoms at some point in their lives, compared to roughly 40% of women. The male urethra is around 20 cm long, about five times the length of the female urethra, which makes it much harder for bacteria to travel up into the bladder. When a man does get a UTI, there’s usually an identifiable reason behind it.
The Bacteria Behind Male UTIs
E. coli causes about 48% of male UTIs, the same bacterium responsible for most female infections. It normally lives in the gut and reaches the urinary tract by migrating from the anal area. Other gut-dwelling bacteria in the same family account for another 24% of cases, and enterococci cause roughly 9%. These bacteria don’t need anything unusual to cause an infection. They just need something that gives them a foothold, whether that’s stagnant urine, a physical obstruction, or a compromised immune system.
Prostate Enlargement: The Most Common Trigger After 50
Benign prostatic hyperplasia, or an enlarged prostate, is the single most common driver of UTIs in older men. As the prostate grows, it squeezes the urethra and makes it harder to fully empty the bladder. The urine that stays behind becomes a breeding ground for bacteria. This mechanism, called urinary stasis, is straightforward: standing water grows things.
Most men experience some degree of prostate enlargement by their 60s and 70s, which is why male UTI rates climb sharply with age. If you’re over 50 and getting recurrent infections, an enlarged prostate is one of the first things your doctor will evaluate.
Kidney Stones and Physical Obstructions
Kidney stones create a strong, well-documented link to urinary infections. A systematic review of 17 studies found that between 19% and 36% of kidney stone cases involved recurrent UTIs, and one long-term study spanning 19 years found that stone formers had a 5.7 times higher risk of developing a UTI compared to people without stones.
Stones cause infections in two ways. First, they can partially block urine flow, creating the same stagnation problem as an enlarged prostate. Second, bacteria can colonize the surface of the stone itself. Researchers have found bacterial colonies on virtually all types of kidney stones, not just the infection-related struvite stones that most people associate with bacteria. Certain bacteria also actively promote stone formation by breaking down urea into ammonia, which then reacts with minerals in urine to build new stones. This creates a cycle where stones cause infections and infections cause stones.
The good news: removing stones surgically resolves the infection problem in most cases. One study found that stone removal prevented recurrent UTIs in about 89% of patients, as long as no fragments were left behind.
Causes in Younger Men
UTIs in men under 50 are unusual enough that doctors typically look for an underlying anatomical abnormality when one occurs. In this age group, structural issues like a narrowed urethra, an abnormal connection between the urinary and digestive tracts, or a problem present since birth are all considered. Sexual activity also plays a role, particularly unprotected anal intercourse, which can introduce gut bacteria into the urethra.
In men younger than 35, infections that look like UTIs are frequently caused by sexually transmitted organisms like chlamydia or gonorrhea rather than typical urinary bacteria. These infections target the urethra and can produce symptoms that overlap heavily with a standard UTI, which is why testing matters.
How to Tell a UTI From an STI
Both UTIs and STIs can cause burning during urination and an increased urge to go, which makes them easy to confuse. A few differences help separate them. UTIs are more likely to cause cloudy urine, blood in the urine, and mild lower abdominal pain without any discharge from the penis. STIs, on the other hand, tend to produce abnormal penile discharge, genital sores or rash, itchiness, and pain during sex. Swollen lymph nodes in the groin also point toward an STI.
It’s possible to have both at the same time. If you’re experiencing urinary symptoms along with discharge or genital sores, testing for both conditions is important because the treatments are different.
Other Risk Factors
Several additional factors raise UTI risk in men:
- Catheter use. Any tube placed in the urethra introduces bacteria directly into the bladder. Hospital-acquired UTIs from catheters are one of the most common healthcare-associated infections.
- Diabetes. Elevated blood sugar impairs immune function and creates a more favorable environment for bacterial growth in urine.
- Weakened immune system. Conditions or medications that suppress the immune system reduce the body’s ability to clear bacteria before they establish an infection.
- Incomplete bladder emptying. Whether caused by nerve damage, medications, or surgery, any condition that leaves residual urine in the bladder increases risk through the same stagnation mechanism as prostate enlargement.
Why Doctors Culture Urine in Men
When women get a straightforward UTI, doctors often prescribe antibiotics based on symptoms alone. For men, the standard approach is different. A urine culture is recommended to confirm the infection and identify the specific bacteria involved. This matters because male UTIs are less predictable in their cause, and choosing the right antibiotic depends on knowing which organism is responsible. A midstream urine sample is over 97% accurate at detecting infection when processed in a lab.
Because male UTIs often have an underlying structural or functional cause, your doctor may also want to investigate further, especially if it’s a first infection or a recurring one. This could involve imaging to check for stones or obstructions, or a prostate exam to assess enlargement.
When a UTI Spreads to the Prostate or Kidneys
One reason male UTIs are taken more seriously than female ones is the risk of the infection spreading. A bladder infection can travel to the prostate, causing bacterial prostatitis. Symptoms include pain between the scrotum and rectum, painful ejaculation, pain in the groin or lower back, and difficulty urinating. Acute bacterial prostatitis also brings fever, chills, and flu-like body aches. It requires a longer course of antibiotics than a simple bladder infection, often lasting several weeks.
If the infection moves upward to the kidneys instead, it becomes pyelonephritis, a more serious condition that causes flank pain, high fever, nausea, and sometimes requires hospitalization. The risk of either complication is higher when an obstruction like a stone or enlarged prostate is trapping bacteria in the urinary tract.