Purpose: The role of the microbiome in the paranasal sinuses and its contribution to sinus mucosal health and disease remains poorly understood. Consequently, we examined the nasal microbiome of chronic rhinosinusitis patients with polyps (CRSwNP), chronic sinusitis without nasal polyps (CRSsNP) and a control population, associated with IL-5 of nasal polyp tissues and postoperative follow-up of CRSwNP patients, in search of nasal microbial community characteristics related to pathogenesis and prognosis of CRSwNP, providing a new perspective for further understanding of the disease.
Methods: The middle meatus secretions of 77 CRSwNP, 36 CRSsNP and 34 non-CRS subjects were collected. The bacterial microbiome composition was detected using high-throughput sequencing technology based on 16S rRNA, and the differences in the nasal microbial diversity among the three groups were compared. At the same time, nasal polyp tissues were collected to detect the expression of IL-5 and analyse its relationship with the structural characteristics of nasal microbial colonies. Postoperative follow-up of patients with CRSwNP was conducted for 1 year to record the recurrence of nasal polyps and analyse the correlation between the recurrence of nasal polyps and IL-5 as well as the characteristics of nasal microbial diversity.
Results: The results showed that the average Sobs index (579.31) of the non-CRS group was significantly higher than that of the CRSwNP group (387.31, P = 0.03). PCoA analysis showed that the microbial distribution in the three groups was mostly similar, with only a few unique to each group. At the phylum level, Actinobacteria and Chlamydia in the non-CRS group were significantly higher than those in the CRSwNP and CRSsNP groups. At the genus level, Corynebacterium and Dolosigranulum in the non-CRS group were significantly higher than those in the CRSwNP and CRSsNP groups. Twenty-five CRSwNP patients had nasal polyps that were IL-5 positive, accounting for 32.47%, and the relative abundance of Enterobacter was 6.37% ± 5.92%, which was significantly higher than 0.58% ± 0.11% in the IL-5 negative group. No significant difference was found after correction (p = 0.026, FDR p > 0.05). One year after surgery, 77 patients with CRSwNP who underwent surgery were successfully followed up, and 12 patients with CRSwNP relapsed, with a recurrence rate of 15.6%. Total nasal symptom scores (TNSS) were significantly higher in the recurrent group than in the nonrecurrent group (P = 0.000). No differences in microbial diversity were found between the CRSwNP populations in the recurrent group and the nonrecurrent group at both the phylum and genus levels. For the nonrecurrent CRSwNP group, the relative abundance of Actinobacteria (PDR P = 0.012) and Corynebacterium (PDR P = 0.003) was higher than that before surgery, and the relative abundance of Bacteroidetes (PDR P = 0.040) was lower than that before surgery. However, for the recurrence CRSwNP group, there was no significant difference in the nasal microbiome between postoperation and preoperation.
Conclusion: In conclusion, microbial dysbiosis in the nasal cavity is associated with the pathogenesis of CRSwNP. In Southwest China, the inflammatory pattern of nasal polyps is not dominated by eosinophilic infiltration of Th2-type inflammation. The recurrence of nasal polyps after ESS may be potentially related to the decrease in protective bacteria and the increase in pathogenic bacteria, and the improvement of postoperative bacterial disorder is correlated with the nonrecurrence of CRSwNP.
Keywords: 16S rRNA; Bacteria; Chronic rhinosinusitis; IL-5; Microbiome; Nasal polyps.