Immediate Versus Substantiated Antibiotic Therapy in Suspected Non-Severe Ventilator-Associated Pneumonia

Inclusion Criteria: * Invasive mechanical ventilation for longer than 48 hours * Respiratory sample collection taken less than two hours ago (at physician discretion, according to local protocol) for a first episode of suspected ventilator-associated pneumonia (meeting the following prespecified criteria) : * new or changing chest X-ray infiltrates * plus at least two of the following: * body temperature ≥38°C or ≤35.5°C, * blood leukocyte count \>12 000/µL or \<4000/µL, * purulent tracheobronchial aspirate. * Age ≥18 years * Informed consent from the patient or next of kin to participation in the trial, or emergency procedure if no next of kin is available * Patients affiliated to a social security system Non-inclusion Criteria: * Criteria for severe ventilator-associated pneumonia defined as: * Vasopressor therapy for onset of septic shock around the time of ventilator-associated pneumonia suspicion * Onset or severe worsening of hypoxemia (PaO2/FiO2\<150 with 60% FiO2 and 10 mm H2O peak expiratory pressure, or patient on veno-venous extracorporeal membrane oxygenation) * Immunosuppression defined as : * leukocytes \<1G/L or neutrophils \<0,5 G/L * within the last 3 months * hematopoietic stem-cell transplant or organ transplant with chronic immunosuppressant therapy * HIV infection with CD4\<50/mm3 * chronic corticosteroid use (\>0.5 mg/kg day for at least one month within the last three months). * Patient already on Antibiotic Therapy of predicted duration ≥4 weeks (endocarditis, spondylodiscitis, abscess...) * Previous ventilator-associated pneumonia suspicion with sampling and/or Antibiotic Therapy for suspected ventilator-associated pneumonia * Previous inclusion in the trial * Patient included in an interventional study on ventilator-associated pneumonia management with the same primary endpoint. * Pregnancy, recent delivery, or breastfeeding * Correctional facility inmate, adult under guardianship * Patient under legal protection * Life expectancy less than 48 h and/or decision not to treat potential pneumonia acquired under mechanical ventilation in the context of limiting/discontinuing treatment. * Organ donor reanimation