Renal stone formation is a multistep process that includes supersaturation of the urine, lack of inhibitory substances, and urinary stasis. Which type of renal calculi is associated with Proteus infection?

Struvite (magnesium-ammonium-phosphate) stones often are associated with infection by urea-splitting bacteria and are the most common cause of staghorn calculi, large stones that form a cast of the renal pelvis. Urea-splitting organisms, which include Proteus, Klebsiella, Staphylococcus species, Providencia, and Corynebacterium, also raise the pH of the urine (>7.2). Surgical treatment is recommended for staghorn calculi. Ref: Manthey D.E., Nicks B.A. (2011). Chapter 97. Urologic Stone Disease. In J.E. Tintinalli, J.S. Stapczynski, D.M. Cline, O.J. Ma, R.K. Cydulka, G.D. Meckler (Eds), Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 7e.