Bacterial colonization of ureteral stents.

The aim of this study was to assess the frequency of bacterial stent colonization and stent-associated bacteriuria, and to evaluate the significance of urinary cultures for identification of colonizing microorganisms. A total of 93 ureteral stents from 71 patients were examined: 9 patients with permanent ureteral stenting due to malignant ureteral obstruction (27 stents), and 62 patients with temporary ureteral stents (66 stents). Bacteriuria and bacterial stent colonization were found in all patients with permanent stents. In patients with temporary stents, colonized stents were found in 69.3% (43/62), mainly in combination with sterile urine (45.2%, 28/62). Mean indwelling times did not differ between patients with sterile urine and sterile stents (11.8 days) and patients with sterile urine and colonized stents (11.2 days). Prophylactic antibiosis in 42/62 temporarily stented patients did not reduce colonization rates compared to patients without antibiotics (70 vs. 65%). Enterococci were the bacteria most frequently cultured from urine and stents. In the present study, ureteral stent colonization rates were 100% in permanently and 69.3% in temporarily stented patients. Antibiotic prophylaxis did not prevent stent colonization and should not be routinely administered. Since urinary cultures correctly identified all colonizing microorganisms in only 21%, removal/replacement and bacteriologic evaluation of ureteral stents may be necessary in case of urosepsis.