What could cause a urinary tract infection in men?

Several things: The most common is incomplete emptying of the bladder because of an enlarged prostate.

Variable: There are multiple causes for a UTI in men depending on the age group. In younger men, it is usually from sexual activity or scarring in the urethra (stricture). In older men, it is usually from an enlarged prostate, urinary retention, bladder stones, or strictures.

Urinary stasis: Inadequate urine drainage favors urinary tract infection. Congenital abnormalities in urinary tract (upj obstruction, posterior urethral valve, vesicoutereal reflux), kidney stone, and enlarged prostate are examples.

Not normal in men...: Though urinary tract infections commonly occur in women; since the urethra in men is longer and farther from the anus, uti's in men aren't common. However, uti's in men all require a work-up to find the underlying cause so it can be addressed: 1.Sexually transmitted infection, 2.Anatomical/physiologic cause (bacteria backwashes), or 3.Obstruction causing urine retention( e.g. Enlarged prostate).

Bacteria in urethra: Most utis are result of bacteria enering the urethra and working their way up to the prostae & bladder. Anthing causing urinary stasis or obstruction, like man enlarged prostae or urthral stricture will promote a uti. Chlamydia and mycoplasma can be sexually transmitted and cause utis. Uncircumcised, particulary men with poor hygiene, are more likely to get utis than those circumcised circumcised.