The role of the pulmonary microbiome in the pathophysiology of lung disease is becoming increasingly well understood. Studies on murine models have highlighted the immunomodulatory and antibacterial activity of certain commensal bacteria, such as S. mitis, and have led to an understanding of their potential therapeutic impact. The investigators will therefore couple their analyses of the respiratory microbiome with an in-depth analysis of mucosal immunity. In particular, they will characterize immune cell types and frequencies using high-dimensional (spectral) flow cytometry and single cell RNA-sequencing. Finally, they will study the mediators exchanged between the microbiome and the host using proteomic and metabolomic analyses of respiratory fluids.

Inclusion Criteria:

• Male or female.
• Age from 18 to 70.
• Indication for scheduled general anesthesia with orotracheal intubation for non-thoracic, non-carcinological, non-septic surgical procedures such as prosthesis (knee or hip), spinal surgery, digestive hernia surgery, gall bladder surgery, maxillofacial surgery (non-exhaustive list).
• Membership of a social security scheme or beneficiary of such a scheme.
• Written informed consent.

Exclusion Criteria:

• Persons under guardianship or trusteeship.
• Pregnant or breast-feeding woman.
• Antibiotic treatment received within 28 days prior to surgery, regardless of the site of infection.
• Acute respiratory pathology within the last 28 days (pneumothorax, bronchitis or pneumonia including Covid).
• History of chronic respiratory disease (asthma, chronic obstructive pulmonary disease, emphysema, lung cancer, cystic fibrosis, etc.).
• Immunosuppression (cancer active or within the last 5 years, HIV, radio-chemotherapy within the last year, organ transplant).
• Chronic inflammatory disease (digestive, osteoarticular, neurological or cutaneous) requiring or having required specific treatment in the last 12 months.
• Type I or II diabetes.
• Steroid treatment within the last 30 days (regardless of dose or duration).