Role of cultural analysis in patients with indwelling ureteral stent submitted to ureteroscopy for stones.

Background: Aim of our study is to analyze the incidence of postoperative infectious complications and to assess its predictors in patients with indwelling ureteral stent treated with ureteroscopy (URS).

Methods: We retrospectively evaluated data of patients treated with URS from January 2017 to July 2018 at our center. We included 88 consecutive patients with available stent culture (SC) and urine culture (UC). Cefoxitin 2 g IV was given as prophylaxis in all patients with negative preoperative UC; otherwise, the choice of antibiotic was based on antibiogram. Ureteral stent was removed before URS procedure and analyzed. No postoperative antibiotic was given. Multivariable logistic regression analysis was built to assess preoperative predictors of postoperative infectious complications.

Results: Nineteen patients (22%) developed postoperative infectious complications and fever was the most common one. E. faecalis, which is not responsive to common prophylaxis schemes in force in our institution, was the most frequent pathogen isolated. Overall, 26% of patients were found to have a discordance between SC and UC. At multivariable logistic regression analysis preoperative SC positivity (Odds Ratio [OR]: 11.00, 95% Confidence Interval [CI]:1.08-111.41, P=0.04) was the only significant predictor of postoperative infectious complications.

Conclusions: About one to five patients treated with URS developed an infectious complication and E. faecalis and E. coli were the most frequent pathogen isolated. A positive SC is the only independent risk factor for postoperative infection: consequently, an early SC analysis could allow a prompt antibiotic therapy in all patients with positive SC even if mildly symptomatic.