Methods for removing bacterial biofilms:: In vitro study using clinical chronic rhinosinusitis specimens

Background: Bacterial biofilms may be involved in refractory chronic rhinosinusitis (CRS), In vitro, we studied methods for removing biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa. Methods: Bacterial isolates were obtained from patients with refractory CRS and were plated and treated with either static administration of citric acid/zwitterionic surfactant (CAZS), saline delivered with hydrodynamic force, or CAZS delivered hydrodynamically. Results were assessed by counting colony-forming units (CFUs) and by confocal scanning laser microscopy (CSLM). Results: All treatments produced significant reductions in CFU counts (p >= 0.002). Hydrodynamic CAZS provided the greatest reduction, decreasing CFU counts from control values by 3.9 +/- 0.3 logs and 5.2 +/- 0.5 logs for S. aureus and P. aeruginosa, respectively (99.9% reduction; p = 0.001). CSLM showed decreases in biofilm coverage, Conclusion: Hydrodynamic delivery of a soap-like surfactant and a calcium-ion sequestering agent may disrupt biofilms associated with CRS. Our results may be relevant to a new approach to refractory CRS.