Parallel to this, the rapid development of genomics has highlighted the role of flora (microbiota) and its link with disease (eg, colitis and intestinal microbiota inflammatory). This area is also emerging in the field of respiratory tract infections, for example in patients with chronic obstructive pulmonary disease (COPD) or asthma. There is no description yet of metagenomics changes in respiratory flora of patients intubated with or without VAP, neither evaluation of the benefits of such an approach in relation to classical microbiology. The investigators believe that studying the respiratory flora of ventilated patients could provide clues to better understand the development of VAP.