Search strategy (January 1980-December 2013) in Medline via PubMed, CENTRAL, and EMBASE. Additionally, we searched databases for registered trials and conference abstracts, as well as reference lists of systematic reviews and included studies. Seven published randomized clinical trials (January 1, 1980 to December 31, 2013) were included in quantitative analyses with no language restrictions. Two independent reviewers collected data. Risk of bias was evaluated with the Cochrane Collaboration tool. We performed a fixed effect analyses due to statistical homogeneity. The primary outcome was urinary tract infection and the secondary was asymptomatic bacteriuria. The effect measure was the risk difference (RD) with 95% confidence interval. The planned interventions were: Antibiotic vs placebo; Antibiotic vs no intervention and Antibiotic vs any other intervention.

3038 patients were found in seven studies. For the primary outcome, we included 5 studies and we found a RR 0.53 CI95% (0.31, 0.90) and a RD-0.012 CI95% (-0.023,-0.002), favoring antibiotic prophylaxis. For asymptomatic bacteriuria we included 6 studies and we found a RR 0.28 CI95% (0.20, 0.39) and a RD-0.055 CI95% (-0.07,-0.039), was found favoring prophylaxis. According to GRADE evaluation, we considered moderate quality of evidence for both outcomes. The subgroup analysis showed that only two studies were classified as having low risk of bias: Cam 2009 and García-Perdomo 2013. They showed no statistical differences (RD-0.009 CI95% -0.03, 0.011).

Based on studies classified as low risk of bias, we found moderate evidence to not recommend the use of antibiotic prophylaxis to prevent urinary tract infection and asymptomatic bacteriuria in patients who undergo cystoscopy with sterile urine in an ambulatory setting.