To Örebro University

Introduction & Objectives: Antibiotic prophylaxis are administered as a routine to decrease the risk for septic complications following transrectal prostate biopsy. Fosfomycin administered 1 h or more prior to biopsy has equal or better infectious complication rates as compared to Ciprofloxacin in both prospective and retrospective studies from countries with high rates of antibiotic resistance. The aim of this study was to investigate if Fosfomycin administered immediately prior to prostate biopsy was as effective as Ciprofloxacin in Sweden, a country with low rates of antibiotic resistance.

Materials & Methods: A randomized, controlled, open, multicenter, non-inferiority-study including men of all ages undergoing transrectal prostate biopsy was performed in the urology departments of three Swedish hospitals. The total number of patients were planned for 3448, divided into low and high infection risk groups. The low-risk group was randomized to either one dose of Fosfomycin 3g or Ciprofloxacin 750mg before biopsy. The high-risk group was randomized to either two doses of Fosfomycin 3g prior to biopsy and one more 24 h after biopsy or Ciprofloxacin 500mg once prior to biopsy and then twice daily for three days. The drugs were administered orally. All patients had a rectal swab for culture before and after biopsy. The endpoint was hospitalisation due to urinary tract infection within 14 days from biopsy, follow-up was performed with a phone interview.

Results: The safety board prematurely interrupted the study after 42 included patients due to an unusual high number of hospitalisations. Four out of 20 patients (20%), three in the low-risk group and one in the high-risk group, had been hospitalised due to urosepsis in the Fosfomycin group. One further patient described fever symptoms but did not seek health care. No patient in the Ciprofloxacin group (n=21) described symptoms of infection from the urinary tract. One patient was lost to follow-up. A one-sided binomial test showed a p-value of <0.001. Two of the four hospitalised patients had a positive blood culture for Pseudomonas Aeruginosa and one had a positive rectal swab culture for Pseudomonas species both before and after biopsy.

Conclusions: The study does not support the use of Fosfomycin administered immediately prior to prostate biopsy. The results may have been affected by the unexpected high number of Pseudomonas infections, a bacteria where Fosfomycin often lack effect. If Fosfomycin is to be used it should be with caution if Pseudomonas has been seen in earlier cultures