Rapidly recurrent renal calculi caused by Ureaplasma urealyticum: a case report.

We report on a patient operated upon 8 times for recurrent bilateral struvite stones. Multiple conventional bacterial cultures had been negative. No etiological agent for the rapidly recurring concrements could be detected until Ureaplasma urealyticum cultures were performed at the time of the seventh operation. Ureaplasma urealyticum was found in the bladder and renal pelvic urine, and in the stones. That operation was followed by appropriate antibiotic treatment (doxycycline), which eradicated the microorganism and no stones recurred for 6 months. The urinary pH, which constantly had been highly alkaline before treatment, was normal as was the ammonium loading test. However, 1 year after the seventh operation the Ureaplasma infection recurred, probably due to sexual transmittance, and a new renal stone was discovered. These findings strongly suggest that Ureaplasma urealyticum can induce the formation of infection concrements.