Rare constituents of the nasal microbiome contribute to the acute exacerbation of chronic rhinosinusitis

Dysbiosis of the nasal microbiome is considered to be related to the acute exacerbation of chronic rhinosinusitis (AECRS). The microbiota in the nasal cavity of AECRS patients and its association with disease severity has rarely been studied. This study aimed to characterize nasal dysbiosis in a prospective cohort of patients with AECRS. We performed a cross-sectional study of 28 patients with AECRS, 20 patients with chronic rhinosinusitis (CRS) without acute exacerbation (AE), and 29 healthy controls using 16S rRNA gene sequencing. Subjective and objective assessments of CRS disease severity during AE were also collected. Compared to healthy controls and patients with CRS without AE, AECRS presented with a substantial decrease of the Corynebacterium_1 and a significant increase of Ralstonia and Acinetobacter at the genus level (LDA score > 2.0 [P < 0.05]). Furthermore, genera with a mean relative abundance (MRA) of less than 1% were defined as rare components based on published studies, then 29 genera with a substantial alteration in AECRS were rare constituents of the microbiome, of which 18 rare genera were highly associated with subjective and objective disease severity. Moreover, a combination of 15 genera could differentiate patients with AECRS with an area under the curve of 0.870 (95% CI = 0.784–0.955). Prediction of microbial functional pathways involved significantly enhanced lipopolysaccharide biosynthesis pathways and significantly decreased folate biosynthesis, sulfur relay system, and cysteine and methionine metabolism pathways in patients with AECRS. The rare nasal microbiota (MRA < 1%) correlated with disease status and disease severity in patients with AECRS. The knowledge about the pattern of the nasal microbiome and its metabolomic pathway may contribute to the fundamental understanding of AECRS pathophysiology.