AUA: Quinolone Resistance May Threaten Prostate Biopsy Prophylaxis

ANAHEIM, Calif., May 29 -- Quinolone antibiotics for prostate-biopsy prophylaxis are showing signs of increased resistance.

A retrospective record review of 1,230 patients who received quinolone prophylaxis before a prostate biopsy during 2004 through 2006 showed that 2.7% (33) had symptoms of infection after biopsy, investigators said at the American Urological Association meeting here.

Twenty-two of the 33 had positive urine or blood cultures, and quinolone-resistant organisms were found in 16 of the 22 (73%), said Joseph Feliciano, M.D., of the State University of New York Downstate Medical School in Brooklyn.

Though the overall rate of quinolone resistance remains low, the rate more than doubled from 1.1% in 2004 to 2.6% in 2006, a non-significant rise (P=0.095), yet providing concern about the possibility of emerging resistance., he said. Additionally, quinolone-resistant organisms often were resistant to multiple antibiotics, but they were highly susceptible to cephalosporins.

"At this time, quinolones are still safe," said Dr. Feliciano. "But when patients come in with infections after prostate biopsy, quinolone resistance should be suspected, and the patient should be treated with cephalosporins."

The study involved patients who had transrectal ultrasound-guided prostate biopsy from January 2004 through October 2006. All patients were given a three-day course of levofloxacin or gatifloxacin one day prior to biopsy. Patients who returned for visits within 30 days after biopsy were questioned regarding infective symptoms, including fever, chills/rigors, elevated white count, and persistent dysuria requiring medical attention and intervention. Additionally, patient cultures were evaluated for patterns of resistance.

The overall rate of infective complications was 2.7%, roughly half of which (1.3%) involved quinolone resistance. Escherichia coli grew in 80% of the cultures, and 90% of those cultures demonstrated quinolone resistance, Dr. Feliciano reported. Quinolone-resistant E. coli also demonstrated resistance to gentamicin (17%), trimethorprim/sulfamethoxazole (47%), piperacillin (70%), and ampicillin (95%). However, the quinolone-resistant organisms exhibited 100% sensitivity to amikacin, ceftazidime, and ceftriaxone.

Overall, the quinilone resistance data do not offer a reason for immediate concern, said Dr. Feliciano. However, stratification of the data by year revealed evidence of a trend toward increasing resistance to quinolone antibiotics in patients undergoing prostate biopsy, a development physicians should watch closely.