Is antibiotic prophylaxis required for flexible cystoscopy? A truncated randomized double-blind controlled trial

To examine the incidence of urinary tract infection (UTI) after flexible cystoscopy (FC) and determine whether prophylactic norfloxacin reduces this incidence compared with placebo.

A double-blind trial was performed, randomizing 234 patients to either 400 mg of norfloxacin or placebo prior to FC. All patients provided a midstream urine specimen (MSU) before the procedure, as well as at day 3 and day 7 after FC. In addition, a telephone questionnaire was performed to correlate the nature and severity of any symptoms associated with UTI.

Interim analysis was performed because of the low recruitment rate, and a significantly lower infection rate than expected meant that the trial was discontinued. There was one symptomatic UTI in the placebo group (0.82%) and one in the norfloxacin group (0.89%). The UTI in the placebo group was de novo, while the infection in the norfloxacin group was secondary to pre-FC bacteriuria. There was no difference in the infection rates in the two groups. The overall infection rate (de novo and secondary to existing bacteruria) after FC was 0.85%.

Infection after flexible cystoscopy is rare and not associated with significant morbidity. A much larger study would be required to determine whether antibiotic prophylaxis significantly reduces the rate of postprocedure UTI.