Defining the biological basis of Staphylococcus aureus carriage (360G-Wellcome-211864_Z_18_Z)

Staphylococcus aureus is major cause of infection worldwide. This bacterium persistently colonises the nose (its natural niche) in around 20% of the population, which increases their risk of S. aureus infection. Why some people carry S. aureus while others never do is not understood, but is likely to reflect a complex trait influenced by multiple factors. This may include the human genome, host immunity, the nasal microbiota, bacterial-nasal epithelial cell interactions and lifestyle choices. We propose that key determinants for S. aureus carriage can be defined in a powered cohort study in which these parameters are established. Our study will capitalise on existing cohorts (INTERVAL & COMPARE) of healthy volunteers who have been extensively characterised through human genome sequencing and phenotypic profiling. We will screen 25,000 INTERVAL participants for S. aureus carriage, and using sequencing methods define their nasal microbiota composition. We will use existing as well as generate additional data on lifestyle. These datasets will be mined during a series of genome-wide and phenotypic association studies to identify factors that influence the nasal microbiota and S. aureus carrier status. Selected phenotypic and genetic variants of interest will then be tested in relevant experimental systems.