Chronic obstructive pulmonary disease (COPD) and bronchiectasis are common chronic respiratory diseases in China. COPD is characterized by irreversible lung function decline due to airway inflammation, emphysema and alveolar destruction. Bronchiectasis is characterized by permanent bronchiectasis, its main clinical symptoms are cough, dyspnea, hemoptysis and recurrent respiratory tract infections. The incidence and prevalence of bronchiectasis have assumed continuously grows in global. Airway microbiota, whose alterations play an important role in the occurrence and development of bronchiectasis, form a complex ecosystem interacted with host cells and various biotic and abiotic factors in the microenvironment. Additionally, mounting evidence suggests that the airway microbiome is associated with COPD phenotypes and endotypes, and that dysbiosis contributes to airway inflammation. However, the mechanisms remain poorly understood, owing to limited knowledge of microbial functional properties, metabolic activities and cross-talk with the host immune system. The investigators aim to collect sputum specimen and perform multi-omic analysis on patients with COPD and bronchiectasis in seven clinical centres in China.

Inclusion Criteria:

• Patients diagnosed with bronchiectasis (according to the Chinese consensus, patient's previous chest CT examination must show bronchiectasis) or COPD (according to GOLD 2022).
• Patients with age ≥18 years old.
• Written informed consent.

Exclusion Criteria:

• Pregnancy or lactation, or those without taking effective contraceptive measures
• Subjects with a history of mental illness or suicide risk, with a history of epilepsy or other central nervous system disorders
• Subjects with a history of alcohol or illicit drug abuse
• Subjects with any of the following pulmonary diseases: active tuberculosis, pulmonary embolism, pneumothorax, multiple huge bullae, uncontrolled asthma, acute exacerbation of chronic bronchitis or extremely severe COPD
• Diagnosis of chronic gastrointestinal disease, heart disease, diabetes, severe renal insufficiency (GFR < 30ml/min) or immunodeficiency
• Participated in any interventional clinical trial within 3 months before enrolment.
• Poor compliance or inability to cooperate as judged by the doctor

Adult patients enrolled in this study should meet the bronchiectasis diagnositc criteria according to the Chinese consensus or COPD diagnositc criteria according to GOLD 2022.