Men get bladder infections when bacteria enter the urethra and travel upward into the bladder, colonizing the lining and triggering inflammation. This is far less common in men than in women, largely because the male urethra is about 20 centimeters (roughly 8 inches) long, giving bacteria a much longer path to travel before reaching the bladder. But several conditions and behaviors can overcome that natural defense, especially as men age.
How Bacteria Reach the Bladder
Nearly all male bladder infections start the same way: bacteria from outside the body enter the opening of the urethra, attach to the urethral lining, and migrate upward toward the bladder. Once they reach the bladder wall, they multiply and cause infection. This ascending route is the primary pathway.
The bacterium E. coli is responsible for about 25% of male UTI cases. That’s a notably smaller share than in women, where E. coli dominates. In men, other bacteria like Proteus, Providencia, Klebsiella, and Pseudomonas account for a larger proportion of infections. When a bladder infection is tied to chronic prostate problems, though, E. coli jumps back to the lead, causing roughly 80% of those cases.
Why the Prostate Plays a Central Role
The prostate gland sits just below the bladder and wraps around the urethra, so problems with the prostate directly affect how well urine flows and how vulnerable the urinary tract is to infection.
Chronic bacterial prostatitis, a lingering low-grade infection of the prostate, is the most common cause of recurring UTIs in men. Bacteria can settle into prostate tissue and persist there even after a course of antibiotics, then periodically seed the bladder with a fresh round of infection. Men who keep getting bladder infections often have an underlying prostate issue driving the cycle.
An enlarged prostate (benign prostatic hyperplasia, or BPH) creates a different but equally important problem. As the prostate grows, typically starting in a man’s 40s or 50s, it squeezes the urethra and partially blocks urine flow. The result is incomplete bladder emptying: urine sits in the bladder longer than it should, giving bacteria a warm, stagnant environment to multiply. The Mayo Clinic notes that this inability to fully empty the bladder directly raises the risk of urinary tract infections, and in some cases, frequent UTIs from BPH eventually require surgery.
Risk Factors for Younger Men
Bladder infections in men under 50 are uncommon but do happen. Two specific factors raise the risk in this age group: being uncircumcised and engaging in anal intercourse. The foreskin can harbor bacteria near the urethral opening, and anal intercourse exposes the urethra to fecal bacteria that cause most UTIs. Beyond those, anything that introduces bacteria near the urethra or disrupts normal urine flow, including catheter use or kidney stones, increases the odds at any age.
Symptoms and How to Tell It Apart From an STI
A bladder infection and a sexually transmitted infection can both cause burning during urination, which is why men sometimes confuse the two. But the patterns differ in useful ways.
A bladder infection typically causes a burning sensation while urinating, a frequent and urgent need to pee (sometimes producing very little), cloudy or slightly bloody urine, and mild pain in the lower abdomen or pelvis. Crucially, there’s usually no abnormal discharge from the penis.
An STI, on the other hand, is more likely to produce abnormal penile discharge, genital sores or rash, pain during intercourse, or itchiness. Blood in the urine leans more toward a UTI, though some STIs can cause it too. If you’re unsure, a urine test can identify bacteria quickly and distinguish between the two.
What Happens if It’s Not Treated
In women, a simple bladder infection sometimes resolves on its own. In men, that’s less likely because the infection often involves the prostate or has an underlying structural cause. Left untreated, bacteria continue to climb upward from the bladder through the ureters to the kidneys, causing pyelonephritis (a kidney infection). From the kidneys, the infection can enter the bloodstream and trigger urosepsis, a life-threatening condition that can lead to organ damage, organ failure, and death. This progression is why bladder infections in men are generally treated more aggressively than in women.
How Treatment Typically Works
Antibiotics are the standard treatment. How long you take them depends on how complicated the infection is. Current guidelines from the Infectious Diseases Society of America recommend 5 to 7 days of antibiotics for most complicated UTIs when the patient is responding well to treatment. But if a prostate infection is suspected, which is common in men with febrile UTIs, treatment typically extends to 10 to 14 days. Men with chronic bacterial prostatitis driving repeat infections may need longer courses or even ongoing low-dose antibiotics to keep infections from returning.
Because male bladder infections frequently have an underlying cause, your doctor will likely want to investigate beyond the infection itself. That could mean checking prostate size, measuring how completely you empty your bladder, or imaging the urinary tract to look for stones or structural abnormalities. Treating the infection without addressing the root cause often means the infection comes back.