Objectives/Hypothesis Clinical improvement in patients with chronic rhinosinusitis (CRS) treated with steroids alone has previously been ascribed to the steroids' anti-inflammatory properties rather than any direct effect on the bacteria. The aim of this study was to determine if commonly used intranasal steroids directly reduce bacterial biofilm production in vitro. Study Design In vitro comparative controlled trial. Methods Staphylococcus aureus biofilms were grown on minimum biofilm eradication concentration device pegs and treated with the commonly prescribed CRS topical steroids fluticasone, mometasone, or budesonide. These were dissolved in vehicle solvents and added to cerebrospinal fluid (CSF) broth. Concentrations (including therapeutic doses) tested for fluticasone and mometasone ranged from 25 μg/200 μL to 400 μg/200 μL, and from 16 μg/200 μL to 2000 μg/200 μL for budesonide. Control pegs were exposed to equivalent volumes of the appropriate solvent/CSF broth. Confocal scanning laser microscopy and COMSTAT software were used to quantify biofilms at 24 hours after treatment. Results Significant differences from control were found for fluticasone at 400 μg/200 μL (difference = -0.3065 μm3/μm2, P =.007), mometasone at 300 μg/200 μL and 400 μg/200 μL (difference = -0.15 μm 3/μm2, P =.006, and difference = -0.9193 μm 3/μm2, P =.034, respectively), and budesonide at 750 μg/200 μL, 1000 μg/200 μL and 2000 μg/200 μL (difference = -1.0137 μm3/μm2, P =.038, difference = -0.6164, P =.009, and difference = -0.1906 μm3/μm2, P =.029, respectively). Conclusions The concentrations of 400 μg/200 μL of fluticasone, 300 μg and 400 μg/200 μL of mometasone, and 750 μg, 1,000μg, and 2,000 μg/200 μL of budesonide directly reduce biofilm production in vitro, outside of the inflammatory milieu.
- Chronic rhinosinusitis
- Staphylococcus aureus