Background|Complicated Urinary Tract InfectionModel for Pathogenesis in the Urinary Tract
Prevention of UTI by VaccinationSpecific Studies in the Mobley LaboratoryReferences
Our population is aging. In the U.S., the proportion of the population aged >65 years is projected to increase from 12.4% (30 million) in 2000 to 19.6% (71 million) in 2030  . In 1997, the U.S. had the highest health-care spending per person aged >65 years ($12,100)  ; nursing home and home health-care expenditures doubled during 1990-2001, reaching approximately $132 billion  . The absolute number of persons >65 years old residing in our 18,000 nursing homes is currently estimated at 1.5-1.9 million residents  . In these facilities urinary incontinence, a very frequent complication is treated with long term (>30 days) urinary catheterization. Nearly 100% of these patients become bacteriuric  , often leading to fever, bacteremia and death  . Proteus mirabilis and related species, Providencia stuartii and Morganella morganii account for more than half of these infections [5, 7] .
Proteus mirabilis, a gram-negative enteric bacterium, differentiates between the vegetative swimmer cell and the hyper-flagellated swarmer cell  . Individuals suffering urinary tract infections (UTI) caused by P. mirabilis and related urease-positive bacterial species often develop bacteriuria, kidney and bladder stones, catheter obstruction due to stone encrustation, acute pyelonephritis, and fever [7, 9, 10] . P. mirabilis is one of the most common causes of UTIs among individuals with long term indwelling catheters, complicated urinary tract infections, and bacteremia among the elderly [7, 11] . As the aging population continues to expand, more individuals will be at risk for P. mirabilis UTI  .