Randomized clinical trial on antimicrobial prophylaxis for flexible urethrocystoscopy.

Objectives: One of the main drawbacks of flexible urethrocystoscopy is the risk of urinary tract infection (UTI). In order to reduce this risk, antimicrobial prophylaxis has been considered, however there is not a unanimous view regarding indications, dosage, type of antibiotic, and so on. To clarify this uncertainty, we practiced a pilot and experimental study aimed at assessing the effectiveness of chemoprophylaxis with 3 grams of fosfomycin trometamol in the prevention of UTI after urethrocystoscopy.

Methods: Sixty patients were entered into a pilot randomized clinical trial between March and August 2011. Thirty patients were assigned to a control group without receiving any antibiotic dose, and the intervention group (30 patients) received 3 g fosfomycin trometamol. Ten days later urine culture and sediment analysis were performed in all patients. Significant bacteriuria was considered from > 105 CFU /ml. One month later a telephone survey was developed to assess urinary symptoms, and assistance to the family doctor. We estimated the cumulative incidence of bacteriuria, pyuria and microhematuria in both groups, and we compared the results using a strategy of analysis per protocol and intention to treat.

Results: The incidence of bacteriuria, pyuria and microhematuria in the control group was 10%, 23.3% and 26.7% respectively and in the intervention groups the values differed depending on the type of analysis. Considering only the 27 patients (per protocol analysis), the incidence would be 11.1%, 37.0% and 29.6% respectively. If we include the three patients who did not completed the study (per intention to treat analysis) and considering their results as negative, the results were 10%, 33.3% and 26.7% respectively. Finally, in the case the three cultures not performed in this group had produced a positive result, the impact would have been 20.0%, 43.3% and 36.7%. In any of the three cases, the differences with the control group were not statistically significant.

Conclusions: In a selected population and with appropriate aseptic measures, antibiotic chemoprophylaxis does not appear to show a clinically relevant reduction in the incidence of UTI in patients undergoing flexible urethrocystoscopy.