MacDermott 1988.

Methods	Study design: randomized controlled study Study dates: not reported Setting: not reported Country: UK
Participants	Inclusion criteria: participants undergoing cystoscopy for the diagnosis, transurethral resection, or follow‐up of transitional cell carcinoma of the bladder Exclusion criteria: history of sensitivity to cephalosporins or penicillins, antibiotics or indwelling catheters in the 7 days preoperatively Sample size: 243 participants entered trial, 26 excluded. Preoperative urine specimens were infected in 28 participants and these were studied as 1 group. Remaining 189 participants divided into 4 groups, depending on preoperative randomization and findings at cystoscopy Age (years): mean: group 1: 68.4 (range 44–81); group 2: 67.7 (range 25–84); group 3: 69.7 (range 52–83); group 4: 67.4 (range 52–82) Sex: not reported
Interventions	Group 1 (n = 47): cystoscopy showed no bladder tumour recurrence, and participants received cephradine 1 g intramuscularly 6 hours preoperatively, 1 g intravenously on induction of the general anaesthetic, and 1 g orally 12 hours postoperatively Group 2 (n = 51): no antibiotic Group 3 (n = 44): cystoscopy showed new or recurrent bladder tumour recurrence, and participants received cephradine 1 g intramuscularly 6 hours preoperatively, 1 g intravenously on induction of the general anaesthetic, and 1 g orally 12 hours postoperatively. Participants had either cystodiathermy or transurethral resection of their bladder tumours Group 4 (n = 47): no antibiotic. Participants had either cystodiathermy or transurethral resection of their bladder tumours
Outcomes	Bacteriuria How measured: infection defined as a pure culture > 105 CFU/mL Time points measured: urine specimens collected prior to first dose of antibiotic, on passing the cystoscope and at 5 days postoperatively Time points reported: not reported Outcomes: group 1: 1/47 participants had bacteriuria; group 2: 8/51 had bacteriuria; group 3: 2/44 had bacteriuria; group 4: 8/47 had bacteriuria Bacterial resistance How measured: not reported Time points measured: urine specimens collected prior to the first dose of antibiotic, on passing the cystoscope and at 5 days postoperatively Time points reported: not reported Outcomes: group 1: 0 participants with bacteriuria were resistant to cephradine; group 2: 2/8 with bacteriuria were resistant to cephradine; group 3: 2 participants with bacteriuria were resistant to cephradine; group 4: 2/8 participants with bacteriuria were resistant to cephradine Adverse events How measured: not reported Time points measured: not reported Time points reported: not reported Outcomes: no adverse effects reported
Funding sources	E. R. Squibb and Sons Ltd for assistance with the funding
Declarations of interest	No information about conflict and interest
Notes	28 participants had infection preoperatively,13 were randomized to receive cephradine and 15 to receive no antibiotics. The postoperative urine specimens showed the infection had cleared in 3 participants who had received only the protocol doses of cephradine. All of the other participants in this group required further treatment for their infections. 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 allocated 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: "Control group received no antibiotic, the trial group received cephradine 1 g intramuscularly 6 h [hours] pre‐operatively, 1 g intravenously on induction of the general anaesthetic and 1 g orally 12 h post‐operatively." Comment: participants in the control group received no antibiotic prophylaxis, while the treatment group received intravenously antibiotic prophylaxis. Unlikely that participants and personnel were blinded to the intervention.
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Quote: "Control group received no antibiotic, the trial group received cephradine 1 g intramuscularly 6 h pre‐operatively, 1 g intravenously on induction of the general anaesthetic and 1 g orally 12 h post‐operatively." Comment: participants not blinded to their treatment. Risk of detection bias for adverse effects was high.
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Comment: bacterial resistance and bacteriuria results were obtained from laboratory. Detection bias for these 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: "Of the 243 patients entering the trial, 26 were excluded (Table 1). Pre‐operative urine specimens were found to be infected in 28 patients and these were studied as one group. The remaining 189 patients were divided into four groups, depending on the pre‐operative randomisation and the findings at cystoscopy." Comment: 189/243 randomized participants (91 participants in intervention group, 98 in control group) were included for analysis of this outcome. 26 participants excluded with reasons, preoperative urine specimens infected in 28 participants and these were studied as 1 group and analyzed. Overall, loss to follow‐up was less and their reasons were given; therefore, judged adequate.
Incomplete outcome data (attrition bias) Minor adverse events	Low risk	Quote: "Of the 243 patients entering the trial, 26 were excluded (Table 1). Pre‐operative urine specimens were found to be infected in 28 patients and these were studied as one group. The remaining 189 patients were divided into four groups, depending on the pre‐operative randomisation and the findings at cystoscopy." Comment: 189/243 randomized participants (91 participants in intervention group, 98 participants in control group) were included for analysis of this outcome. 26 participants excluded with reasons, preoperative urine specimens infected in 28 participants and these were studied as 1 group and analyzed. Overall, loss to follow‐up was less and their reasons were given; therefore, judged adequate.
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	Low risk	Quote: "Of the 243 patients entering the trial, 26 were excluded (Table 1). Pre‐operative urine specimens were found to be infected in 28 patients and these were studied as one group. The remaining 189 patients were divided into four groups, depending on the pre‐operative randomisation and the findings at cystoscopy." Comment: 189/243 randomized participants (91 participants in intervention group, 98 participants in control group) were included for analysis of this outcome. 26 participants excluded with reasons, preoperative urine specimens infected in 28 participants and these were studied as 1 group and analyzed. Overall, loss to follow‐up was less and their reasons were given; therefore, judged adequate.
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.