The ureters and bladder normally prevent urine from backing up toward the kidneys, and the flow of urine from the bladder helps wash bacteria out of the body. In men, the prostate gland produces secretions that slow bacterial growth. In both sexes, immune defenses also prevent infection. Despite these safeguards, though, infections still occur. Who Is at Risk Scientists are not sure why women have more urinary infections than men.
Some people are more prone to getting a UTI than others.
An enlarged prostate gland also can slow the flow of urine, thus raising the risk of infection. A common source of infection is catheters, or tubes, placed in the bladder. A person who cannot void, is unconscious, or is critically ill, often needs a catheter that stays in place for a long time. Some people, especially the elderly or those with nervous system disorders who lose bladder control, may need a catheter for life. Bacteria on the catheter can infect the bladder, so hospital staff take special care to keep the catheter sterile and remove it as soon as possible.