Evidence for pathogenicity of Ureaplasma urealyticum for the upper urinary tract derived from animal models.

In limited clinical studies ureaplasmas have been cultured from the upper urinary tracts of some patients with struvite renal calculi and interstitial renal diseases. Struvite calculi were also produced in rats by inoculation of human ureaplasmas. We found that a type 8 strain of Ureaplasma urealyticum survived for at least 21 days and replicated following inoculation into the experimentally obstructed canine upper urinary tract. Development of severe chronic interstitial renal inflammation was accompanied by 10-fold rises in systemic anti-urea-plasmal antibody titers. This animal model should prove to be useful for investigating the potential role of ureaplasmas as opportunistic pathogens of the upper urinary tract.