Evaluation of Polyethylene Glycol-Based Antimicrobial Coatings on Urinary Catheters in the Prevention of Escherichia coli Infections in a Rabbit Model.

Introduction and Objective: Catheter-associated urinary tract infections are a major cause of patient morbidity and mortality. Despite many attempts to design biomaterials that might reduce the risk, none has had a profound impact on reducing the incidence of this most common nosocomial infection. Recent in vitro work, however, has shown promise for a silver-based biomaterial coating composed of methoxylated polyethylene glycol 3,4-dihydroxyphenylalanine (mPEG-DOPA3) in reducing uropathogen attachment and biofilm formation. The aim of this work was to investigate whether these results translate into a meaningful impact on infection development and bacterial adherence in an in vivo rabbit model. Materials and Methods: New Zealand white rabbits were randomized into groups of 12 and had the following catheters inserted: Group 1-uncoated polyurethane, Group 2-Coating A (mPEG-DOPA3 + 2 mg/mL AgNO3), and Group 3-Coating B (mPEG-DOPA3 + 10 mg/mL AgNO3). Each rabbit was challenged with 108 colony-forming units of Escherichia coli GR-12 instilled directly into the bladder at the time of catheter insertion and urine was monitored over 7 days for bacterial counts. Catheters were retrieved and evaluated for encrustation and attachment analysis, and tissues collected for histopathologic characterization and bacterial invasion. Results: Urinary bacterial colony counts were lower among rabbits in the Coating A group vs controls (4/11 vs 10/12, respectively) (p = 0.029), and there were fewer rabbits with invasive infections (3/12 vs 9/12, p = 0.02). More encrustation was observed among animals in the Coating B group vs controls (7.22 vs 2.69 mg/cm2, p = 0.033). There were no significant differences in tissue effects between groups. Conclusions: The use of a mPEG-DOPA3 urinary catheter coating effectively reduced urinary pathogen counts, while not causing adverse tissue effects in this model. Further clinical evaluation is warranted.