Composition and dynamics of the adult nasal microbiome

Background: The nasal microbiome, a dynamic assemblage of commensals and opportunistic pathogens, is crucial to human health. Results: Using cross-sectional data from 1,608 adults and longitudinal sampling of 149 individuals over 8–22 months, we identified nine nasal community state types (CSTs), defined by bacterial density and indicator taxa, with varying stability and transition patterns. Core taxa such as Staphylococcus epidermidis and Cutibacterium acnes were highly stable, while opportunistic pathogens like Staphylococcus aureus and Moraxella catarrhalis had shorter residence times. Interactions between Dolosigranulum pigrum and Corynebacterium pseudodiphtheriticum/propinquum were linked to reduced S. aureus colonization. Host factors, including age and biological sex, significantly shaped microbiome dynamics: men exhibited higher bacterial densities and pathogen colonization, while women showed more stable commensal-dominated CSTs. Aging was associated with shifts in CST frequencies, with declining S. aureus and increasing Enterobacterales. Conclusions: These findings reveal potential strategies by modulating nasal microbiome dynamics to reduce pathogen colonization and improve health.