The Efficacy of Fosfomycin as Antibiotic Prophylaxis for Transrectal Prostate Biopsy and Impact on Lower Urinary Tract Symptom After Biopsy: A Prospective Study.

Objective: Due to fluoroquinolone resistances worldwide, valid alternatives for anti- biotic prophylaxis for transrectal ultrasound-guided prostate biopsy are needed, thus, we aimed to evaluate the efficacy, safety, and tolerability of prophylactic fosfomycin versus other oral prolonged antibiotic regimens, in preventing complications after transrectal ultrasound-guided prostate biopsy.

Methods: In this prospective study, patients submitted to transrectal ultrasound- guided prostate biopsy were divided into 2 groups according to the prophylactic antibiotic scheme performed: "short" (2 fosfomycin doses) versus "long" (antibiotic ≥ 8 days). One week and 1 month after transrectal ultrasound-guided prostate biopsy, we assessed complications' occurrence (lower urinary tract symptoms, fever, sepsis, hemorrhage) and adverse drug reactions.

Results: We included 244 patients (fosfomycin n=178, "long" antibiotic n=66). The only significant difference between groups was higher lower urinary tract symptom incidence 1 month after transrectal ultrasound-guided prostate biopsy in fosfomy- cin patients (16.85% vs. 6.06%, P=.031). However, after 1 week, lower urinary tract symptoms were tendentially frequenter on "long" antibiotic group (31.81% vs. 25.84%, P = .059). Infectious and hemorrhagic complications rate, adverse drug reactions, and recurrence to health services were similar between groups, and significantly decreased between the first week and first month.

Conclusion: Antibiotic prophylaxis seems to impact lower urinary tract symptoms after transrectal ultrasound-guided prostate biopsy. Fosfomycin may provide slightly better outcome on the immediate period, while "long" antibiotic courses lead to significantly less lower urinary tract symptoms 1 month post-transrectal ultrasound-guided pros- tate biopsy, perhaps by preventing incipient prostatitis phenomena. Future directed studies should clarify these findings. Still, it seems feasible to ally fosfomycin advan- tages with noninferior safety, efficacy, and tolerability, allowing to reserve "long" regimens to other contexts. This is especially relevant in centers where transperineal biopsies are still not possible.