Antibiotic pretreatment of hydrogel ureteral stent.

Purpose: To compare bacterial adhesion to hydrogel-coated and uncoated ureteral stents. The antimicrobial activity of coated and uncoated stents treated with commonly used antibiotic solutions also was evaluated.

Materials And Methods: Hydrogel coated and uncoated stent segments were dipped in different antibiotic solutions (ciprofloxacin, gentamicin, and cefazolin). Normal saline was used as the control. The segments were incubated in separate broths of Escherichia coli and Enterococcus faecalis to reach the log phase. They were sonicated to free the bacteria, and colony-forming units were determined after 48 hours. To evaluate antibacterial activity, hydrogel-coated and uncoated stent segments were dipped in the above-mentioned antibiotic solutions. Normal saline was used as the control. Segments were incubated in separate Mueller-Hinton agar plates inoculated with E. coli or Enterococcus faecalis, and the zones of inhibition were determined at 24 hours. The duration of antibacterial activity for each bacterium-antibiotic combination also was studied.

Results: Hydrogel coating did not significantly reduce bacterial adhesion. Zones of inhibition around stent pieces dipped in antibiotic solutions differed with the organism and the antibiotic. Cefazolin produced a significantly larger zone of inhibition with hydrogel-coated stent, but the duration of antibacterial activity was similar to that of uncoated stent. Hydrophilic coating significantly increased the duration of antibacterial activity of ciprofloxacin and gentamicin.

Conclusion: Hydrogel coating on the surface of ureteral stents does not prevent or reduce bacterial adhesion. However, after antibiotic treatment, stents exhibit antibacterial activity in the local environment at greater intensity and for a longer time, depending on the bacterium-antibiotic combination.