Is fosfomycin a potential treatment alternative for multidrug-resistant gram-negative prostatitis?

B. J. Gardiner, A. A. Mahony, A. G. Ellis, N. Lawrentschuk, D. M. Bolton, P. T. Zeglinski, A. G. Frauman, M. L. Grayson

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Background. Multidrug-resistant gram-negative bacterial (MDR-GNB) infections of the prostate are an increasing problem worldwide, particularly complicating transrectal ultrasound (TRUS)-guided prostate biopsy. Fluoroquinolone-based regimens, once the mainstay of many protocols, are increasingly ineffective. Fosfomycin has reasonable in vitro and urinary activity (minimum inhibitory concentration breakpoint ≤64 g/mL) against MDR-GNB, but its prostatic penetration has been uncertain, so it has not been widely recommended for the prophylaxis or treatment of MDR-GNB prostatitis.Methods. In a prospective study of healthy men undergoing a transurethral resection of the prostate for benign prostatic hyperplasia, we assessed serum, urine, and prostatic tissue (transition zone [TZ] and peripheral zone [PZ]) fosfomycin concentrations using liquid chromatography-tandem mass spectrometry, following a single 3-g oral fosfomycin dose within 17 hours of surgery.Results. Among the 26 participants, mean plasma and urinary fosfomycin levels were 11.4 ± 7.6 g/mL and 571 ± 418 g/mL, 565 ± 149 minutes and 581 ± 150 minutes postdose, respectively. Mean overall prostate fosfomycin levels were 6.5 ± 4.9 g/g (range, 0.7-22.1 g/g), with therapeutic concentrations detectable up to 17 hours following the dose. The mean prostate to plasma ratio was 0.67 ± 0.57. Mean concentrations within the TZ vs PZ prostate regions varied significantly (TZ, 8.3 ± 6.6 vs PZ, 4.4 ± 4.1 g/g; P =. 001). Only 1 patient had a mean prostatic fosfomycin concentration of <1 g/g, whereas the majority (70%) had concentrations ≥4 g/g.Conclusions. Fosfomycin appears to achieve reasonable intraprostatic concentrations in uninflamed prostate following a single 3-g oral dose, such that it may be a potential option for prophylaxis pre-TRUS prostate biopsy and possibly for the treatment of MDR-GNB prostatitis. Formal clinical studies are now required.

Original languageEnglish
Pages (from-to)e101-e105
Number of pages5
JournalClinical Infectious Diseases
Issue number4
Publication statusPublished - 15 Feb 2014
Externally publishedYes


  • fosfomycin
  • infection
  • prostate
  • prostatectomy
  • urology

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