Investigation of nazal microbiome in chronic rhinosinusitis with nasal polyposis patients and determining the relationship between nazal microbiome and disease severity

Introduction: Multiple inflammatory mechanisms dynamically interact in the development of chronic rhinosinusitis with nasal polyps (CRSwNP). The disruption of the relationship between host and environmental factors on the mucosal surface causes the development of inflammation. Microorganisms constitute the most important part of environmental factors. It has been possible to identify microorganisms of the microbiome rapidly and accurately with the new generation sequencing techniques. Materials and Methods: 28 volunteers were included in the study (10 control group, 10 non-operated CRSwNP, 8 previously operated CRSwNP). Swab samples were taken from the middle meatus under endoscopic examination from all participants. After DNA extraction, a library was created with the Swift Amplicon 16S + ITS kit and sequenced with Illumina Miseq. Sequence analysis was performed using QIIME2. UNITE v8.2 database for ITS and Silva v138 for 16S rRNA. Results: Patients' LM and SNOT-22 scores were 18.6 ± 4.7 and 42.6 ± 19.5 in the primary disease group, 16.5 ± 5.1 and 32.0 ± 11.4 in the recurrent disease group, respectively. SNOT-22 scores did not correlate significantly with LM scores. The most dominant bacteria in the study group were Firmicutes (44.5%), Proteobacteria (25.2%), Actinobacteria (24.6%) as phylum and Staphylococcus (22.2%), Corynebacterium (16.2%), Sphingomonas. (9.2%) as genus. The abundance of Actinobacteria in the control group was higher than the recurrent disease and primary disease groups. Mean relative abundance of Corynebacterium (MRA) was significantly higher in the control group compared to the patients (p = 0.007). Streptococcus, Moraxella, Prevotella, Peptostreptococcus and Micrococcus were significantly higher in the patient groups compared to the control group. The dominant fungal genus in all groups was the genus Malassezia. MRA in the control group was significantly higher than the patient groups. Staphylococcus; showed a statistically significant negative correlation with Dolosigranulum and Fusobacterium (p <0.05). Corynebacterium had a positive correlation with Lawsonella and Anaerococcus, and a negative correlation with Neisseria, Prevotella, Fusobacterium and Peptostreptococcus (p <0.05). Conclusion: Nasal microbiome of CRSwNP patients shows greater inter-individual variation than the control group. Corynebacterium is less abundant in patients with CRSwNP compared to the control group. Malassezia is the dominant fungus genus in the nasal cavity and paranasal sinuses and correlates positively with the abundance of Corynebacterium.