[Experimental bladder stone production by Ureaplasma urealyticum].

We examined the relationship between struvite stone formation and Ureaplasma urealyticum in male Wister rats by inoculating U. urealyticum and implanting a zinc disc into the bladder surgically. Cultures of U. urealyticum and pH measurements in urine obtained by forced urination were done on days 2 and 6 after operation. Half of the rats were killed 7 days after the operation and the remaining half 14 days after the operation. A total of 46 rats, consisting of 10 rats in the control group and 36 rats inoculated with U. urealyticum, were studied. U. urealyticum was weakly virulent, because it was not detected in the urine culture on day 2 in 10 of the 36 rats inoculated with the organism, and showed a tendency towards spontaneous elimination in the other rats. Urinary pH was elevated slightly by the presence of U. urealyticum. Struvite stones were formed in 52% of the rats by the inoculation on of U. urealyticum, and 69% and 71% of the positive rats in urine culture for U. urealyticum on day 2 and day 6 respectively. The stones tended to be larger the longer U. urealyticum was detected in urine. U. urealyticum may play a role in struvite stone formation, but not a major role.