Urinary tract infection (UTI) is the most common infection in patients with SCI and is a major cause of morbidity and mortality in this population. The bladder of patients with SCI, especially those who have indwelling catheters, is often colonized by bacteria that may or may not cause symptoms of UTI. Bacteria that do not cause symptoms are usually considered benign colonizers and are often left untreated because they may afford some protection against symptomatic infection with more harmful bacteria.