Rodrigues 1994.

Methods	Study design: prospective, randomized study Study dates: February 1992 to February 1993 Setting: outpatient Country: Brazil
Participants	Inclusion criteria: negative urine culture harvested 72 hours prior to cystoscopy Exclusion criteria: history of recurrent urinary infections or factors related to urinary infection, such as those with urolithiasis, vesicoureteral reflux, or use of bladder catheters Sample size: 90 participants Age (years): median 58 (range 24–84) Sex: 59 men, 31 women
Interventions	Group 1 (n = 30): single‐dose fosfomycin trometamol 3000 mg, 2 hours before procedure Group 2 (n = 30): sulphamethoxazole 800 mg + trimethoprim 160 mg every 12 hours starting 2 hours before procedure and continuing for 3 days Group 3 (n = 30): placebo tablet 2 hours before procedure
Outcomes	Bacteriuria How measured: positive urine cultures ≥ 105 CFU/mL in asymptomatic men and women or 103 CFU/mL in symptomatic women Time points measured: all participants underwent clinical evaluation and urine cultures of control 30 days after procedure Time points reported: not reported Outcomes: 2/30 participants in group 1, 3/30 participants in group 2, and 8/30 participants in group 3 had bacteriuria Adverse events How measured: not reported Time points measured: not reported Time points reported: not reported Outcomes: adverse effects were identified in 3 participants, all belonging to group 2, 2 cases with epigastric pain and 1 case of hives, in the latter being necessary to interrupt the antibiotic prophylaxis and administration of antihistamine
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: "The patients were randomized into three equal groups." Comment: method for generation of random sequence not given.
Allocation concealment (selection bias)	Unclear risk	Comment: no information regarding concealment of randomization.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "3,000 mg of fosfomycin trometamol in single dose (Group I); 800 mg of sulfamethoxazole and trimethoprim 160 mg every 12 hours continuing for three days (Group II); a tablet of placebo (Group III)." Comment: no information about whether the placebo and antibiotics had the same appearance or whether participants could see a difference between them.
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	Comment: no information about whether investigators were blinded to the investigation. Detection bias for adverse events was unclear.
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	Low risk	Quote: "Side effects were identified in three patients, all belonging to Group II." Comment: 90/90 randomized participants (30 in control group, 60 in intervention group) included for analysis of this outcome.
Incomplete outcome data (attrition bias) Minor adverse events	Low risk	Quote: "Side effects were identified in three patients, all belonging to Group II." Comment: 90/90 randomized participants (30 in control group, 60 in intervention group) were included for analysis of this outcome.
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.
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.