Abstract

Objective: This study aimed to describe the morphological and ultrastructural characteristics of bacterial biofilms on the sinonasal mucosa in patients with chronic rhinosinusitis, thereby contributing to a better understanding of the role of biofilms in pathogenesis and treatment orientation. Subjects and Methods: A cross-sectional descriptive study was conducted on 11 sinonasal mucosal specimens collected from 11 patients diagnosed with chronic rhinosinusitis according to the EPOS 2020 criteria. The specimens were processed using a standard protocol and examined under scanning electron microscopy at magnifications ranging from 1,500 to 5,000 × to evaluate surface structure and the presence of biofilms. Results: Ultrastructural images revealed significant damage to the mucosal surface, including loss or deformation of cilia, along with the accumulation of mucus and cellular debris. Biofilms were observed in 8 out of 11 samples (72.7%), presenting as complex and heterogeneous three-dimensional structures. The bacteria (spherical and rod-shaped) are densely distributed at a rate of 91%, enclosed within an amorphous three-dimensional extracellular matrix (EPS). The tight binding between the bacteria and EPS demonstrates the ultrastructural characteristics of the mature biofilm. Conclusion: My procedure for preparing chronic sinus tissue samples for scanning electron microscopy in this report has enabled the detection of the widespread presence of biofilms on the nasal and sinus mucosa in patients with chronic rhinosinusitis, exhibiting typical ultrastructural features. These findings contribute to clarifying the role of biofilms in pathogenesis and are significant in diagnosis, prognosis, and guiding biofilm-targeted treatment strategies.