[Experimental magnesium ammonium phosphate lithiasis induced by Ureaplasma in the rat].

Struvite urinary stones are commonly associated with infections by urease possessing bacteria (Proteus). Ureaplasma urealyticum, a genital mycoplasma, is predominantly located in the human genito-urinary tract and produces urease. Its possible role in the formation of infection stones was studied in the rat model described by Friedlander and Braude. Struvite bladder stones were produced in 60% of Sprague-Dawley male rats after infection of ureaplasmas (serotype 1, 2, 3, 7) into the renal medulla. Mycoplasma hominis, another genital mycoplasma, produced bladder stones in only 10% of animals. A kinetic study showed that pure struvite stones appeared into the bladder 4 to 5 days after inoculation and that U. urealyticum did not usually remain viable more than 6 days. Acetohydroxamic acid and doxycycline prevented the formation of the stones.