Changes in the sinus microbiome in health and chronic rhinosinusitis

Purpose of review This article synthesises the recent sinus microbiome literature, identifying common themes in research findings as well as surveying the varied methodological approaches used across these studies. Recent findings While there remains no clear consensus as to which microbes define dysbiosis in chronic rhinosinusitis (CRS), certain trends are emerging. Increasingly, the evidence points towards a pathogenic role in the overabundance of Moraxella , Haemophilus and Pseudomonas species, whilst the genera Cutibacterium, Anaerococcus and Dolosigranulum tend towards commensalism. However, the roles of the most common genera in the sinus microbiome, Staphylococcus and Corynebacterium, remain uncertain. Given the diversity and abundance of species within these genera, species and function-level analyses are needed to clarify their contributions to the aetiopathogenesis of CRS. Comprehensive study of the sinus microbiome in healthy individuals further shows that community composition shifts with age, suggesting that dysbiosis may manifest differently across the lifespan. Beyond bacteria, growing evidence highlights the importance of fungi and viruses, underscoring the need to incorporate these microbionts into future analyses. Summary Progress towards a clinically meaningful consensus will require standardised approaches to sequencing, species-level resolution in these analyses, and consideration of the heterogeneous clinical and immunological subgroups of CRS.