Study of infective (secondary) renal calculus formation in vitro.

The factors of infective calculus formation and the conditions favoring their prevention were studied by examining in vitro the role of the most common representative of urease-producing bacteria, Proteus mirabilis. The stream of Proteus-containing urine was found to form deposits of magnesium ammonium phosphate, carbonate apatite and ammonium-urate on the glass surfaces. Application either of mandelic acid or of Gentamycin was found to reduce the production of these deposits, and their joint application proved fully preventive to their formation. Gentamycin applied in saline acidified with mandelic acid was capable of dissolving previously formed crystals. A medication of this composition is advocated for preventive use after surgery for staghorn calculi. The necessity for continuing peroral medication and specific antibacterial therapy for months is emphasized.