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.