Commonest stone in case of UTI: (A) Phosphate, (B) Urate, (C) Cysteine, (D) Calcium oxalate
Answer is A. Phosphate or struvite stones are infection stones associated with urea-splitting organisms i.e. Proteus, Pseudomonas, Providencia, Klebsiella, Staphylococci and Mycoplasma. The high ammonium concentration desired from urea-splitting organisms results in an alkaline urinary pH, required for the precipitation of phosphate crystals. Ref : Bailey & Love 25/e p1296