Bacteria that enter the
urethra and travel up the
urinary tract are the usual cause of
urinary tract infections (UTIs). Bacteria that
normally live in the
large intestine and are present in feces (stool) are
the most common source of infection. Sexual intercourse may move bacteria
into the urinary tract, especially in women.
Catheters, which are small, flexible tubes inserted
into the bladder to allow urine to drain, are a common source of bacterial
infection in people who are in hospitals or who live in long-term care
Sometimes bacteria traveling through the blood or
lymph system cause kidney or bladder
Kidney stones, an
enlarged prostate in men, and structural problems in
the urinary tract can contribute to UTIs by limiting the body's ability to
eliminate urine completely.
Women who have repeated UTIs may have inherited genes that make them more likely to get these infections.