Microbial colonization and evolution in the lower airways of people with bronchiectasis

Microbial Colonization Distribution and Adaptive Evolution of Lower Respiratory Tract in Bronchiectasia Patients.

Observational Second Affiliated Hospital, School of Medicine, Zhejiang University · NCT04966793

This project will test whether monthly sputum microbiome profiling and Pseudomonas genome sequencing over three years can track how bacteria colonize and change in people with bronchiectasis.

Quick facts

Study typeObservational
Enrollment1850 (estimated)
Ages18 Years to 79 Years
SexAll
SponsorSecond Affiliated Hospital, School of Medicine, Zhejiang University Academic / other
Locations1 site (Hangzhou, Zhejiang)
Trial IDNCT04966793 on ClinicalTrials.gov

What this trial studies

Researchers will collect qualified sputum samples from clinically stable bronchiectasis patients every month for three consecutive years and perform metagenomic sequencing to characterize lower respiratory tract microbiome changes. Pseudomonas aeruginosa isolates will be recovered and whole-genome sequenced to analyze adaptive evolution related to virulence, quorum sensing, and drug resistance under host pressure. The team aims to link microbiome dynamics and bacterial evolution to acute exacerbations and longer-term prognosis. Findings are intended to identify microbiome-based markers and potential targets for prevention or treatment strategies.

Who should consider this trial

Good fit: Ideal participants are clinically stable adults with CT-confirmed bronchiectasis, a history of two or more chest infections in the prior year, and chronic Pseudomonas aeruginosa colonization who can provide monthly sputum samples.

Not a fit: Patients actively exacerbating, current heavy smokers, those with cystic fibrosis, active tuberculosis, uncontrolled asthma, allergic bronchopulmonary aspergillosis, or who are pregnant or breastfeeding are excluded and unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, the work could allow earlier prediction of exacerbations and identify microbiome-targeted approaches to reduce infections and improve outcomes.

How similar studies have performed: Previous longitudinal microbiome studies have linked bacterial community shifts to exacerbations, but tracking whole-genome adaptive evolution of Pseudomonas in bronchiectasis is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Bronchiectasis patients in clinically stable period;
* Two or more chest infections in the previous year;
* Chest CT confirmed bronchiectasis (bronchial to arterial ratio \>1).
* Chronic colonization of pseudomonas aeruginosa and was clinically stable in 6 months prior to the study.

Exclusion Criteria:

* deterioration of illness (defined as at least 24 hours of three or more of the following symptoms: increased cough, increased sputum volume, purulent sputum, hemoptysis, increased dyspnea, increased wheezing, fever ((≥38°C) or discomfort, the attending physician agrees that antibiotic treatment is required);
* current smokers, or former smokers who have stopped smoking less than 1 year ago, have a history of more than 15 packets of age, or CT showed as emphysema;
* cystic fibrosis patients;
* active allergic bronchopulmonary aspergillosis;
* active tuberculosis patients;
* patients with poor asthma control;
* pregnant or breastfeeding women.

Where this trial is running

Hangzhou, Zhejiang

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions BronchiectasisMicrobiology
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.