Asuero 1989.

Methods	Study design: prospective randomized control study Study dates: not available Setting: 1 hospital Country: Spain
Participants	Inclusion criteria: people with negative preoperative urine cultures Exclusion criteria: allergy to penicillins, indwelling catheter, easily bleeding during manipulation Sample size: 46 Age (years): overall median: 65 (51–78) Sex: not available
Interventions	Group 1 (n = 23): no antibiotic prophylaxis Group 2 (n = 23): cefuroxime 750 mg intravenously 1 hour preoperatively and 2 more doses administered at 12 and 24 hours after surgery
Outcomes	Systemic UTI How measured: not reported Time points measured: not reported Time points reported: not reported Outcomes: no participant had symptoms suggestive of a UTI Asymptomatic bacteriuria How measured: not reported Time points measured: urine cultures performed on 5th day and 1 month postoperatively Time points reported: not reported Outcomes: control group: 16/23 participants had bacteriuria 5 days after cystoscopy, and 2/23 had bacteriuria 1 month after cystoscopy; treatment group: 3/23 had bacteriuria 5 days after cystoscopy, and 5/23 had bacteriuria 1 month after cystoscopy Bacterial resistance How measured: not reported Time points measured: bacteria cultures from urine performed 5 days after cystoscopy Time points reported: not reported Outcomes: control group: 16 participants with positive urine cultures, 9 of them they showed no sensitivity to cefuroxime; treatment group, 3 participants were all resistant
Funding sources	No information about funding
Declarations of interest	No information about conflict and interest
Notes	In the antibiotic prophylaxis group, all participants with negative blood cultures in the 3rd postoperative day, and 4 participants in the control group had bacteraemia. 3 participants showed an acute epididymitis after cystoscopy, but this study did not report which group they came from. No email address available for contacting the corresponding author for further information.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "We have carried out a prospective study on 46 patients, these 46 patients were randomly divided into two groups." Comment: method for generation of random sequence not given.
Allocation concealment (selection bias)	Unclear risk	Comment: no information regarding the concealment of randomization.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "A first control group of 23 patients who were not administered antibiotic prophylaxis, a second group of 23 patients who were administered 750 mg." Comment: participants in control group were not administered antibiotic prophylaxis, while the treatment group receive intravenous antibiotic prophylaxis. Unlikely that participants and personnel were blinded to intervention.
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Quote: "A first control group of 23 patients who were not administered antibiotic prophylaxis, a second group of 23 patients who were administered 750 mg." Comment: participants were not blinded to their treatment, the risk of detection bias for subjective outcomes, i.e. symptoms suggestive of UTI after cystoscopy was high.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Quote: "When cultures were positive postoperative urine, the sensitivity of the germ to cefuroxime titrated were tested." Comment: since bacterial resistance was evaluated by urine culture from laboratory, results were objective and probably not influenced by blinding or not.
Incomplete outcome data (attrition bias) Systemic UTI	Low risk	Quote: "no participant had symptoms suggestive of a urinary tract infection." Comment: 46/46 participants (23 participants in each arm) included for analysis of this outcome, this risk of bias was low.
Incomplete outcome data (attrition bias) Symptomatic UTI	Low risk	Quote: "no participant had symptoms suggestive of urinary tract infection." Comment: 46/46 participants (23 participants in each arm) included for analysis of this outcome, this risk of bias was low.
Incomplete outcome data (attrition bias) Serious adverse events	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Minor adverse events	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Localized UTI	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Asymptomatic bacteriuria	Low risk	Quote: "Urine cultures performed the 5th postoperative day were positive in three patients in the prophylaxis group (13%) remain negative in the remaining 20 (87%). By contrast, in the control group, these cultures were positive in 16 (69.6%) and negative in 7 of them (30.4%)." Comment: 46/46 participants (23 participants in each arm) included for analysis of this outcome, this risk of bias was low.
Incomplete outcome data (attrition bias) Bacterial resistance	Low risk	Quote: "Three patients in the prophylaxis, isolated germs were resistant, whereas in the control group of 16 patients with positive urine cultures 9 of them they showed no sensitivity." Comment: all included participants were included for analysis of this outcome. 46/46 participants (23 participants in each arm) included for analysis of this outcome, this risk of bias was low.
Selective reporting (reporting bias)	Unclear risk	Comment: data reported on all outcomes specified in methods section, but there was no access to trial protocol/registration to further assess selective reporting.
Other bias	Low risk	Comment: no other bias detected.