Those little friends in our noses
Reviewed by Hassan Mohammed

Human microbiota plays an important role in both health and disease including metabolism, immunomodulation, and a potential role in chronic inflammatory conditions such as chronic rhinosinusitis (CRS). The authors aimed to investigate the sinonasal microbiome using 16S rRNA gene sequencing to describe the normal microbiome of nose and sinuses in healthy and CRS subjects. This was a multicentre, international collaborative in 13 centres across nine countries. Subjects included controls and patients with CRS. Data collected included SNOT‑22. A total of 532 samples including 338 CRS, of which 212 were with polyps, were analysed. The most common bacteria in healthy patients were Corynebacterium and Staphylococcus species, composing 78% of microbiome, and found in 80-90% of samples. The results were not significantly different in patients with CRS without polyps. In those with polyps, Corynebacterium was significantly reduced while Streptococcus was increased when compared to controls. There were geographical variations in microbiome even between centres from the same country. The top five abundant bacteria were Corynebacterium, Staphylococcus, Streptococcus, Haemophilus and Moraxella. Authors concluded that understanding the sinonasal microbiome may provide insights to the upper airway functionality in health and disease. This is an interesting study in terms of revealing the composition of the microbiome of nose and sinuses. However, the presence of the same microbiome in both healthy and inflamed nose create, rather than answer, questions. 

The international sinonasal microbiome study: A multicentre, multinational characterization of sinonasal bacterial ecology.
Paramasivan S, Bassiouni A, Shiffer A, et al.
ALLERGY
2020;75:2037-49.