At their admission in Raymond Poincaré hospital in the long-term ventilation unit for a ventilation check-up, patients with a long-term tracheostomy and suffering from a neurological or neuromuscular disease will be included in the study if they have no sign of pneumonia and no contact with a hospital structure within a month. These exclusion criteria allow to focus on non-decompensating patient with a respiratory flora not hospital-acquired and not modified by antibiotics.