Bacteriuria following extracorporeal shock wave lithotripsy of infection stones

Extracorporeal shock wave lithotripsy effectively pulverizes infected (struvite) renal calculi. However, after treatment minute residual fragments that may harbor bacteria and cause persistent bacteriuria remain in the renal collecting system for months. We investigated prospectively the incidence of persistent Proteus mirabilis bacteriuria after extracorporeal shock wave lithotripsy among 15 consecutive women with Proteus mirabilis urinary tract infections and struvite calculi. All patients received parenteral gentamicin for 3 to 8 days (mean 4.7 days) immediately before and after extracorporeal shock wave lithotripsy. Oral antimicrobials then were administered for 14 to 34 days (mean 25 days). Ten patients have maintained a sterile urine or experienced urinary reinfection by other organisms during 8 to 19 months (mean 13 months) of subsequent bacteriological surveillance. Of these 10 patients 9 had residual fragments. Five patients had Proteus mirabilis bacteriuria after 1 to 7 months of surveillance, including 3 with residual fragments. The mean stone size, methods and duration of renal drainage procedures, and duration of antimicrobial therapy were similar for the 2 patient groups. Proteus mirabilis was isolated from the cultures of only 3 of 11 retrievable stone fragments. In contrast to intact infected renal calculi, residual stone fragments after extracorporeal shock wave lithotripsy often are susceptible to sterilization with antimicrobials.