Large-scale characterisation of the nasal microbiome redefines Staphylococcus aureus colonisation status.

Staphylococcus aureus colonises the nose in humans, with individuals defined as persistent, intermittent or non-carriers. Unlike the gut microbiome, the nasal microbiome has not been studied in large numbers of people. Here, we define the nasal microbiome in ~1100 individuals from the CARRIAGE study (ISRCTN: ISRCTN10474633) and combine with S. aureus culture data. We identify seven community state types (CST), including two CSTs more common in females. Approximately 70% of those who are persistently colonised with S. aureus have a CST dominated by S. aureus, while non-carriers are distributed across the other six CSTs. Intermittent carriers are not a unique state but have microbiomes that resemble non- or persistent carriers. Persistent carriage is positively associated with S. aureus abundance, and negatively associated with three Corynebacterium species, Dolosigranulum pigrum, Staphylococcus epidermidis, and Moraxella catarrhalis; the microbiome can be exploited with machine learning to accurately predict the persistence of S. aureus colonisation. Finally, we find that certain S. aureus lineages are better adapted to colonisation than others. Our data provides a comprehensive view of the nasal microbiome with respect to S. aureus colonisation, describing two key states: a S. aureus dominated CST in which S. aureus shapes the microbiome, and CSTs in which S. aureus is rare or absent.