Comparison of a combined regimen of fosfomycin and ciprofloxacin with ciprofloxacin alone as antimicrobial prophylaxis for transrectal prostate biopsy in the era of high fluoroquinolone-resistant rectal flora.

Background: To assess the prophylactic effect of fosfomycin (FM) and ciprofloxacin combinations for infectious complications of transrectal ultrasound-guided prostate biopsy (TRUSPB) compared to that of ciprofloxacin alone.

Methods: In total, 1,578 patients were enrolled and were divided into two groups according to the prophylactic antibiotics. Group 1 (n = 1234) received ciprofloxacin on the day of the biopsy and for an additional 1-2 days, whereas Group 2 (n = 334) was given FM in addition to ciprofloxacin in the same manner as Group 1. The primary outcome was overall infectious complications within 1 month of TRUSPB. The secondary outcome was the risk factors of infectious complications after TRUSPB.

Results: Infectious complications occurred in 31 patients (2.5%) and 1 patient (0.3%) in Groups 1 and 2, respectively. Our results indicated that fluoroquinolone (FQ) and FM significantly reduced the risk of infectious complications compared to FQ (relative risk: 0.12; 95% confidence interval 0.02-0.87, = 0.015). Based on the multivariate analysis, previous antibiotic exposure (odds ratio [OR] = 3.59, = 0.026), and the addition of FM (OR = 0.12, = 0.038) were associated with infectious complications. Based on the rectal swab, FQ resistance was 28.0% (n = 294) in total. FQ resistance in the FQ and FM group was higher than that in the FQ group (n = 178, 54.9% vs. n = 116, 16.0%, < 0.001).

Conclusion: The combination of ciprofloxacin and FM exhibited reduced infectious complications after TRUSPB compared with ciprofloxacin monotherapy and may be applicable in the era of the high abundance of FQ-resistant rectal flora.