Efficacy of anti-biofilm gel, chitogel-mupirocin-budesonide in a sheep sinusitis model

Background: The search for effective topical anti-inflammatory and antibiofilm delivery to manage recalcitrant chronic rhinosinusitis (CRS) continues to be elusive. The ideal topical treatment aims to provide adequate contact time for treatment agents to exert its effect on sinus mucosa. Our study presents the in vivo efficacy of chitogel (CG), combined with anti-inflammatory agent budesonide and antibiofilm agent mupirocin (CG-BM) for treatment of S. aureus biofilms. Methods: In established sheep sinusitis model, 15 sheep were randomised into three groups (5 sheep, n=10 sinuses, per treatment): (I) twice daily saline flush (NT), (II) CG with twice daily saline flush, and (III) CG-BM with twice daily saline flush for 7-days. The anti-inflammatory effect was graded by an independent blinded pathologist. The antibiofilm effect was assessed using LIVE/DEAD BacLight stain and confocal scanning laser microscopy. Results: No significant differences were observed in histopathology between all groups. A significant reduction in biofilm biomass was shown using COMSTAT2 in CG-BM treated sheep compared to NT controls (P<0.05, One-way ANOVA, Kruskal-Wallis test). Conclusions: CG-BM is effective against S. aureus biofilms in a sheep sinusitis model and could represent a viable treatment option in the clinical setting for recalcitrant CRS.