Garcia‐Perdomo 2013.

Methods	Study design: multicentre randomized controlled trial Study dates: 1 March 2011 to 30 April 2012 Setting: performed in 2 cities in Colombia (Cali and Bogota). The participating centres were: Urological Salus Clinic (Cali), Hospital Universitario San Ignacio (Bogota), ESENSA Foundation (Cali), Farallones Maternal and Child Clinic (Cali), and Colsubsidio Clinic (Bogota) Country: Colombia
Participants	Inclusion criteria: men and women aged ≥ 18 years undergoing cystoscopy for any non‐urgent indication on an outpatient basis; negative urine culture results before the procedure and provided written informed consent prior to participation. Exclusion criteria: participants who could not be followed up; allergy to antibiotics; taking other medications which could interact with the study drugs or for the purpose of prophylaxis for other health conditions (e.g. prosthetic heart valve, heart murmur, prosthetic orthopaedic, or vascular); taking antibiotics at the time of the procedure; history of permanent urethral catheter; immunosuppression; spinal cord injury requiring intermittent catheterization; or required a urethral catheter after the study procedure. Sample size: 290 participants included and 285 participants randomized. Age (years): mean placebo group: 59 (SD 14.8): mean treatment group: 58 (SD 15.4). Sex: placebo group: 94 men and 44 women; treatment group: 90 men and 48 women.
Interventions	Group 1 (n = 138): placebo tablet similar in appearance to antibiotic administered to the treatment group administered 30–60 minutes before procedure Group 2 (n = 138): oral levofloxacin 500 mg administered 30–60 minutes before procedure
Outcomes	Symptomatic UTI How measured: presence of irritative symptoms of UTI with a positive urine culture > 105 CFU/mL Time points measured: 3rd–10th day after procedure Time points reported: not available Outcomes: placebo group: 4/138 had UTI after cystoscopy; treatment group: 1/138 had UTI after cystoscopy Asymptomatic bacteriuria How measured: positive urine culture > 105 CFU/mL for 1 micro‐organism in a midstream sample of urine, without systemic symptoms or irritative symptoms of the urinary tract Time points measured: 3rd–10th day after procedure Time points reported: not reported Outcomes: placebo group: 20/138 had bacteriuria after cystoscopy; treatment group: 8/138 had bacteriuria after cystoscopy Minor adverse events How measured: questionnaire Time points measured: 3rd–10th day after procedure Time points reported: not reported Outcomes: control group: 1/138 participants had pruritus; treatment group: 1/138 participants had nausea
Funding sources	No information about funding
Declarations of interest	No conflict of interest with any of the researchers involved in study.
Notes	Information that rigid cystoscope was used for examination and some participants required manipulation during cystoscope were also included was obtained from corresponding author.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Permuted block randomization with variable sized blocks to ensure a similar number of participants in each group." Comment: random sequence generation performed adequately.
Allocation concealment (selection bias)	Low risk	Quote: "Treatment assignments were kept in sealed, opaque, consecutively numbered envelopes, which were opened in the order of participant arrival at each center in order to conceal the allocation to which study group each patient would be assigned." Comment: allocation concealment performed adequately.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Participants, researchers, and treating physicians were blinded to whether or not participants received antibiotics or placebo. The placebo tablet of identical presentation and weight to levofloxacin 500 mg tablet." Comment: blinding of participants and personnel performed adequately.
Blinding of outcome assessment (detection bias) Subjective outcomes	Low risk	Quote: "Principal investigator could not identify participants received the active drug or not, and participants were blinded about their treatments." Comment: detection bias for symptomatic UTI, asymptomatic bacteriuria, and minor adverse events low due to proper blinding.
Blinding of outcome assessment (detection bias) Objective outcomes	Unclear risk	Comment: not applicable, since the objective outcome of drug resistance was not reported.
Incomplete outcome data (attrition bias) Systemic UTI	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Symptomatic UTI	Low risk	Quote: "285 patients were randomized. No urine culture was performed for 9 (3.2 %) patients after the procedure (3 patients in the antibiotic group and 6 patients in the placebo group). There were no significant differences between the nine patients lost to follow‐up and those who remained in the study. The analyses include 138 patients in each study arm." Comment: overall, loss to follow‐up was less and their reasons given; therefore, judged adequate.
Incomplete outcome data (attrition bias) Serious adverse events	Low risk	Quote: "285 patients were randomized. No urine culture was performed for 9 (3.2 %) patients after the procedure (3 patients in the antibiotic group and 6 patients in the placebo group). There were no significant differences between the nine patients lost to follow‐up and those who remained in the study. The analyses include 138 patients in each study arm." Comment: overall, loss to follow‐up was less and their reasons given; therefore, judged adequate.
Incomplete outcome data (attrition bias) Minor adverse events	Low risk	Quote: "285 patients were randomized. No urine culture was performed for 9 (3.2 %) patients after the procedure (3 patients in the antibiotic group and 6 patients in the placebo group). There were no significant differences between the nine patients lost to follow‐up and those who remained in the study. The analyses include 138 patients in each study arm." Comment: overall, loss to follow‐up was less and their reasons given; therefore, judged adequate.
Incomplete outcome data (attrition bias) Localized UTI	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Asymptomatic bacteriuria	Low risk	Quote: "285 patients were randomized. No urine culture was performed for 9 (3.2 %) patients after the procedure (3 patients in the antibiotic group and 6 patients in the placebo group). There were no significant differences between the nine patients lost to follow‐up and those who remained in the study. The analyses include 138 patients in each study arm." Comment: overall, loss to follow‐up was less and their reasons given; therefore, judged adequate.
Incomplete outcome data (attrition bias) Bacterial resistance	Unclear risk	Comment: outcome not reported.
Selective reporting (reporting bias)	Low risk	Comment: trial was publicly registered in the Australian New Zealand Clinical Trials Registry ACTRN12611000750987. All prespecified outcomes in protocol were reported.
Other bias	Low risk	Comment: no other bias detected.