Epidemiological study aiming to describe the carriage (nasal, throat, groin, rectal and colonic) of S. aureus in patients without chronic digestive disease who are going to have a colonoscopy for cancer screening. The carriage will be analyzed globally and the similarity of strains isolated from each site will be analyzed using molecular tools. The aim of this study is to better estimate the digestive reservoir of S. aureus to better prevent endogenous infections due to this bacterium.