Proposal and clinical validation of a perioperative algorithm enhancing antimicrobial stewardship in substitution urethroplasty.

Objective: To evaluate the impact of a standardized antibiotic stewardship protocol on three subsequent endpoints in patients undergoing urethroplasty.

Methods: Men undergoing bulbar substitution urethroplasty between January 2009 and December 2016 were stratified by urine culture (UCx) at the time of surgery (sterile non-sterile) and were subjected to a standardized algorithm for urinalysis and antimicrobial therapy. We performed quantitative and qualitative exploration of UCx results and the microbial spectrum. The ability of the algorithm to improve antibiotic stewardship was tested by three endpoints: (a) immediate (UCx 2 days postoperatively), (b) short-term (21-day infectious complications), and (c) long-term (retreatment-free survival [RFS]). Statistical analyses included bivariate comparisons. The Kaplan-Meier estimators were used to compare RFS between the groups. The multivariable Cox regression was used to evaluate the independent effect of UCx status at the time of surgery on RFS.

Results: Of 374 men, 235 (63%) had a sterile and 139 (37%) a non-sterile culture at the time of surgery. The proportion of sterile cultures at the time of surgery (63%) was significantly improved to 82% 2 days postoperatively (<0.001). There were 16 (4.3%) patients with infectious complications with no difference between patients with sterile versus non-sterile culture (=0.6). At median follow-up of 29 months, there was no difference in RFS (84%) between patients with sterile versus non-sterile culture (=0.3). Positive UCx was not a predictor of recurrence after multivariable adjustment (=0.5).

Conclusion: A standardized protocol such as the one introduced improves antibiotic stewardship through frequent testing and culture-specific treatment. This is crucial in avoiding unnecessary antimicrobial treatment, and reducing infectious events and adverse effects of a positive UCx on long-term stricture recurrence.