A urinary tract infection (UTI), or bladder infection, is an infection involving the kidneys, ureters, bladder or urethra that is caused by bacterial overgrowth in the bladder’s interior walls. It leads to pain during urination, a frequent need to urinate and fever. The culprit in at least 90 percent of UTIs is a type of bacteria called Escherichia coli, better known as E. coli. If you're a woman, your chance of getting a UTI is high; some experts rank your lifetime risk of getting one as high as one in two—with many women having repeat infections, sometimes for years on end. UTIs are much more common in adults than in children, but about 1 to 2 percent of children do get them. In the U.S., UTIs account for more than 7 million visits to medical offices and hospitals each year. The most common causes of a UTI include sexual intercourse, overconsumption of sugar, pregnancy, antibiotic use, hormone imbalances and injury to the area.