Effectiveness of fosfomycin tromethamine prophylaxis in preventing infection following transrectal ultrasound-guided prostate needle biopsy: Results from a large Canadian cohort

•Rates of infection following transrectal ultrasound-guided prostate biopsy (TRUSPB) are increasing.•Risk factors for post-TRUSPB infections were analysed.•Risk factors included prophylactic regimen, urological co-morbidities and diabetes.•Fosfomycin tromethamine (FMT) is inferior to ciprofloxacin for prophylaxis of post-TRUSPB infections.•FMT was not effective in preventing post-TRUSPB urinary sepsis. Rates of infection following transrectal ultrasound-guided prostate biopsy (TRUSPB) are increasing. The aim of this study was to evaluate the effectiveness of fosfomycin tromethamine (FMT) prophylaxis in preventing post-TRUSPB infectious complications. This nested case–control study included patients undergoing TRUSPB in a Canadian tertiary-care hospital who developed post-TRUSPB bacteraemia or urinary tract infection. Four prophylaxis periods were defined: (i) ciprofloxacin, low-resistance period (CIPRO-LOW), 2002–2009; (ii) ciprofloxacin, high-resistance period (CIPRO-HIGH), 2010–October 2013; (iii) oral FMT, one dose (FOSFO1), December 2013–September 2015; and (iv) oral FMT, two doses (FOSFO2), November 2015–June 2016. Incidence rates of the infection were calculated. TRUSPB (n=9391) resulted in 138 cases of urinary sepsis (58% with bacteraemia). The incidence rates were 1.8% (CIPRO-HIGH), 3.5% (FOSFO1; P=0.004 vs. CIPRO-HIGH) and 2.7% (FOSFO2; P=0.19 vs. CIPRO-HIGH). Although Escherichia coli remained the predominant pathogen with fosfomycin-based regimens, the proportion of infections caused by Klebsiella spp. was higher (20/66; 30.3%) than with ciprofloxacin-based regimens (2/77; 2.6%; P