Nasal Microbiota in Immune Disorders: Bacterial and Fungal Colonization Patterns and Aspergillus Detection Methods

BackgroundThe human respiratory tract hosts a complex microbial ecosystem. The host immune status plays an important role in regulating the microbial composition at different body sites, including the nasal cavity.ObjectiveThis study investigated the effects of immune disorders on nasal microbial colonization and explored Aspergillus detection methods in immunodeficient hosts.MethodsNasal swabs from healthy volunteers, patients with allergic airway disease, and immunodeficient patients were analyzed using 16S rRNA bacterial and ITS2 fungal microbiome analyses. Aspergillus colonization in immunodeficient individuals was examined using conventional methods (galactomannan testing, quantitative PCR, and fungal culture). The effects of nasal irrigation on fungal colonization were also evaluated.ResultsNo significant differences in the overall microbial composition were found between the healthy, allergic, and immunodeficient groups; however, distinct features were observed within each group. Immunodeficient patients showed higher Aspergillus DNA concentrations and positive culture rates than healthy controls. Nasal irrigation significantly decreased Aspergillus DNA concentration.ConclusionThis study highlights the complex relationship between the immune system and airway microbiota. Although microbiome analysis may not be optimal for analyzing upper respiratory tract microbiology in immunomodulated patients, nasal irrigation could potentially reduce fungal colonization in immunocompromised individuals at risk of developing infections.