LAUSR

Alkaline-encrusted pyelitis is a rare and chronic infectious disease of the urothelium, characterized by renal pelvicaliceal calcific encrustations also known as struvite stones. This condition first described in the bladder in 1914 was called encrusted cystitis.1 In 1985, Soriano et al. detectedCorynebacteriumurealyticum (C. urealyticum) in four cases of bladder encrustations.1 In fact, C. urealyticum, a gram-positive, slowgrowing, urease-producing bacterium,with a particular tropism for the urinary tract, is the most frequent causative organism of kidney struvite encrustation.1,2 In 1984, Takebe et al. reported Ureaplasma urealyticum, another urease producing bacterium, as a cause of urinary tract infection and struvite formation.3 In 1992, alkaline encrusted pyelitis was first described.4 To the best of our knowledge, U. urealyticum has never been described as the causative microorganism of encrusted pyelitis in a kidney graft. We thereafter present a case of Ureaplasma-induced encrusted pyelitis in a 28-year-old kidney transplant recipient.