Recurrent Infection Stones with Apparently Negative Cultures. The Case for Blind Antibacterial Treatment

Summary Infection stones in the urinary tract are always associated with infection with a urease‐producing, urea‐splitting organism. The most common of these organisms are easy to culture and identify and can be treated early either with an appropriate antibiotic or with an anti‐urease agent. Ureaplasma urealyticum and Corynebacterium urealyticum are urease‐producing organisms which are difficult to grow; their presence and effects frequently go undetected and untreated. Other organisms, as yet unknown, may also be involved in the same process. We report the first series of 8 patients with recurrent infection‐type stones likely to have been caused by a “hard to grow” organism. Five patients never had a positive culture; in 2 patients 1 of 10 urine cultures grew a coagulase‐negative Staphylococcus and in 1 patient the same organism was grown from a stone but never in the urine. The clinical course of all of these patients was significantly improved after blind treatment with antibiotics and in one case with an anti‐urease agent.