Adhesion of to epithelial cells: an approach to study interactions within the nasal microbiota.

is a skin and mucous commensal bacterium of warm-blooded animals. In humans, the nose is the main ecological niche of , and nasal carriage is a risk factor for developing an endogenous infection. nasal colonization is a multifactorial process, involving inter-species interactions among the nasal microbiota. The objectives of this study were to characterize the microbiota of carriers and non-carriers of and to demonstrate the importance of inter-species relationships in the adhesion of , a key step in nasal colonization. First, we characterized the nasal microbiota from 30 carriers and non-carriers by a culturomic approach. We then evaluated the adhesion of , first alone and then along with other bacteria of the nasal microbiota. To do that, we used an model to measure the interactions among bacteria in the presence of epithelial cells. Analysis of the nasal microbiota of the carriers and non-carriers of made it possible to observe that each microbiota has specific features in terms of composition. However, this composition differs significantly between carriers and non-carriers mainly through two bacterial groups: coagulase-negative staphylococci and corynebacteria. In a second part, adhesion of to epithelial cells showed competition between and these bacteria, suggesting a limitation of nasal colonization by . These findings demonstrate the existence of a negative correlation between and other species which inhibits adhesion and could limit nasal colonization.