Oral fosfomycin for the treatment of chronic bacterial prostatitis

Abstract

Background: Chronic bacterial prostatitis (CBP) is a difficult-to-treat infection as only a few antibiotics achieve therapeutic concentrations in the prostate. Data on the efficacy and safety of oral fosfomycin for the treatment of CBP are limited.

Objectives: To analyse the efficacy and safety of fosfomycin in CBP due to MDR pathogens.

Methods: In a prospective observational study, an oral regimen of 3 g of fosfomycin q24h for 1 week followed by 3 g q48h for a treatment duration of 6-12 weeks was administered. The outcome was clinical and microbiological cure rate at the end of treatment (EOT) and rate of relapse at 3 and 6 months.

Results: The study included 44 patients. The most common pathogen was Escherichia coli (66%), followed by Klebsiella spp. (14%) and Enterococcus faecalis (14%). Most strains were MDR (59%) and 23% had an ESBL phenotype; 33 of 44 strains were resistant to fluoroquinolones, but all were susceptible to fosfomycin (median MIC for Gram-negative pathogens 1.5 mg/L). In 25 patients, treatment was administered for 6 weeks, whereas in the remaining 19 patients it was prolonged to 12 weeks based on the presence of calcifications in the prostate. Cure rate was 82% at EOT and 80% and 73% at 3 and 6 months accordingly. Microbiological eradication was achieved in 86% and 77% at EOT and at 6 months, respectively. Failure was observed in 12 patients. The most common adverse event was diarrhoea (18%).

Conclusions: Oral fosfomycin, particularly in the era of MDR prevalence, represents an attractive, safe and effective alternative to fluoroquinolones for the treatment of CBP.

Figure 1.

Suggested diagnostic algorithm of evaluation of patients with CBP. *Indicates that this is applicable for bacteria susceptible to fosfomycin with an MIC <16 mg/L. FQN, fluoroquinolone; FOF, fosfomycin; SXT, trimethoprim/sulfamethoxazole; MIN, minocycline.