Urinary tract infections (UTIs) affect over 7 million men and women per year and cost the health care industry over 1 billion dollars annually. The incidence of UTI increases markedly in elderly institutionalized persons and leads to excessive antimicrobial usage, emergency room visits, hospitalization, sepsis, and death. The use of antimicrobials to prevent UTI in elderly nursing home patients is not recommended and is fraught with problems such as adverse reactions, drug interactions, and the development of drug-resistant organisms. There is no accepted method of preventing UTI in residents of nursing homes, a vulnerable and understudied population with significant morbidity from UTI.