Urinalysis findings are not predictive of positive urine culture in patients with indwelling stents

Abstract

Introduction: Indwelling stents produce symptoms and urinalysis findings mimicking urinary tract infection (UTI). In this study, we investigated the correlation of urinalysis findings with urine culture in patients with indwelling ureteral stents. Materials and methods: All patients with ureteral stents who underwent stent removal in urology clinic from July 2013 to January 2015 and had urine culture available immediately prior to stent removal were included in this study. Urine culture results as well as age, gender, duration of indwelling stent, and reason for stent placement were collected. Results: A total of 122 patients were included in this study. The two most common reasons for ureteral stent placement included urolithiasis (65.6%) and renal transplant (22.1%). Red blood cell (RBC), leukocytes and nitrite were positive in 92.9%, 70.2% and 17.9% of urine samples respectively. Only 17 patients (13.9%) had positive urine culture. Although renal transplant patients had significantly longer duration of stent retention, no statistically significant difference was noted in rate of positive urine culture compared to urolithiasis patients (p = 1.0). Among patients with positive urine culture, 62.5% had resistant bacteria to common antibiotic treatments and two patients had yeast in urine culture (12.5%). The duration of stent retention did not correlate with bacterial resistance. Multivariate analysis failed to show significant correlation of gender, reason for stent, stent duration, RBC and nitrite with positive urine culture. Conclusions: Positive findings on urinalysis in patients with indwelling ureteral stent have poor correlation to positive urine culture and therefore the use of urine culture to diagnose UTI is warranted.