Determination of microbiological characteristics and risk factors associated with bacteriuria and symptomatic urinary tract infection in patients with retained ureteral stents: an observational study

BACKGROUND: The maintenance of ureteral stents is vital in patients with severe ureteral stricture or ureteral obstruction. This study aimed to identify microbiological characteristics and factors associated with bacteriuria and symptomatic urinary tract infection (UTI) in these patients. METHODS: This study is an observational cross-sectional study. From August 2018 to January 2021, urine samples from 307 consecutive patients who required stent indwelling and had replaced ureteral stents more than once were collected before the replacement procedure and analyzed by microbiological testing. Patient demographics, laboratory test results, and data on dependent functional capacity and indwelling urethral catheter use were collected from all patients. Additionally, ureteral stenting duration and number of previous ureteral stent replacements were reviewed. The primary endpoint was the incidence rate of bacteriuria and extended-spectrum beta-lactamase (ESBL)-producing bacteria. The secondary endpoint was the factors predisposing patients with ureteral stents to bacteriuria, ESBL-producing bacteria, and the development of symptomatic UTIs. RESULTS: Bacteriuria was observed in 187 patients (60.9%). Among the bacteria identified in urine, Escherichia coli was the most commonly isolated microorganism, followed by Enterococcus, Candida species, Staphylococcus species, Klebsiella, and Pseudomonas. Using multivariate analysis, bacteriuria was significantly associated with old age, female sex, presence of diabetes mellitus, impaired renal function, and longer duration of ureteral stenting. ESBL-producing bacteria were detected in 52 isolates (27.8%). The incidence of ESBL-producing bacteria in urine culture was associated with old age and longer ureteral stenting duration. Additionally, symptomatic UTIs developed in 22 patients (7.2%). Dependent functional capacity, impaired renal function, and longer ureteral stenting duration were significantly associated with symptomatic UTIs. CONCLUSIONS: Infections related to ureteral stents showed a specific microorganism profile and resistance pattern compared to community-acquired UTIs. Additionally, we identified the factors associated with bacteriuria and symptomatic UTI in patients with retained ureteral stents and deduced that these may be associated with better outcomes in patients with retained ureteral stents.