Assessment of biofilm by nasal cytology in different forms of rhinitis and its functional correlations

Background: Recently, it has been reported that nasal cytology in light microscopy can identify biofilms, which appear as cyan-stained "Infectious Spots". We assessed by the same method and in the same population, the presence of biofilms in different nasal disorders, and estimated if a correlation with the functional grade of obstruction existed. Methods: Subjects suffering from different nasal disorders, after a detailed clinical history and ENT examination, underwent nasal fibroendoscopy, skin prick test, rhinomanometry and nasal cytology. The presence of biofilm was linked to the type of disease and to the grade of obstruction. Results: Among 1,410 subjects previously studied, the infectious spot was found in 107 patients (7.6%), and this percentage reached 55.4% in subjects with cytologic signs of infectious rhinitis (presence of bacteria/fungi). Biofilms were largely more frequent in patients with adenoid hypertrophy (57.4%), followed by nasal polyposis (24%), chronic rhinosinusitis (9.5%) and non-allergic rhinitis (7.6%). Nasal cytology was normal in the remaining patients, where no infectious spot was detectable. Statistical analysis showed that nasal resistances were significantly higher in presence of biofilms in patients with adenoid hypertrophy (p=0.003), nasal polyposis (p<0.001), chronic rhinosinusitis (p=0.018) and septal deviation (p=0.001). Conclusion: The results demonstrate that biofilm is present not only in infectious rhinitis, but also in inflammatory and/or immune-mediated diseases. The presence of biofilms significantly correlates with the degree of nasal obstruction as assessed by rhinomanometry.