Si 1997.

Methods	Study design: randomized controlled study Study dates: January 1990 to December 1994 Setting: not reported Country: China
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Sample size: 252 cystoscopes performed on 206 participants Age: not reported Sex: 140 men, 61 women
Interventions	Group 1 (n = 64): simple cystoscopy examination without other manipulation. No antibiotic Group 2 (n = 52): simple cystoscopy examination without other manipulation. Norfloxacin 400 mg 2 hours before cystoscopy, then 200 mg twice after cystoscopy, interval 6 hours Group 3 (n = 41): cystoscopy examination with manipulations, e.g. biopsy. No antibiotic Group 4 (n = 44): cystoscopy examination with manipulations, e.g. biopsy. Norfloxacin, 400 mg 2 hours before cystoscopy, then 200 mg twice after cystoscopy, interval 6 hours
Outcomes	Bacteriuria How measured: positive urine cultures ≥ 105 CFU/mL or > 5 white blood cells/high power field in microscope Time points measured: urine cultures before cystoscopy and 3 days after procedure Time points reported: not reported Outcomes: 3/64 participants in group 1, 2/52 in group 2, 7/41 in group 3, and 2/41 in group 4 had bacteriuria
Funding sources	No information about funding
Declarations of interest	No information about conflict and interest
Notes	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: "Patients were randomly assigned into 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: "Participants in the treatment group received 400mg norfloxacin, while the control group received no antibiotic." Comment: participants in control group did not receive antibiotics, while participants in treatment group received antibiotics. Unlikely that participants and personnel were blinded to the intervention.
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	Comment: subjective outcomes of systemic and localized symptoms after cystoscopy; adverse events not reported.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Comment: bacteriuria evaluated by urine culture was regarded as the primary outcome, the result was obtained from laboratory. Detection bias for this outcome was unlikely to be influenced by the unblinded design.
Incomplete outcome data (attrition bias) Systemic UTI	Unclear risk	Comment: outcome not reported.
Incomplete outcome data (attrition bias) Symptomatic UTI	Unclear risk	Comment: outcome not reported (bacteriuria was reported, but without differentiating whether participants had symptoms or not).
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	Unclear risk	Comment: outcome not reported (bacteriuria was reported, but without differentiating whether participants had symptoms or not).
Incomplete outcome data (attrition bias) Bacterial resistance	Unclear risk	Comment: outcome not reported.
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.