Sputum microbiome profiling in COPD: beyond singular pathogen detection.

Area of Science:

• Microbiology
• Pulmonary Medicine
• Genomics

Background:

• Culture-independent sequencing reveals a complex respiratory microbiome previously undetectable.
• The role of the microbiome in chronic obstructive pulmonary disease (COPD) and its potential as a biomarker are under investigation.
• Sputum, an accessible sample, is crucial for studying the COPD microbiome, though it represents only part of the respiratory tract microbiome.

Purpose of the Study:

• To review the principles of high-throughput microbiome sequencing techniques.
• To summarize current literature on sputum microbiome profiling in COPD.
• To discuss limitations and future directions in COPD microbiome research.

Main Methods:

• Review of existing literature on microbiome sequencing and COPD.
• Focus on 16S rRNA gene sequencing, whole metagenome, metatranscriptome, and metabolome profiling.
• Discussion of standardized protocols for longitudinal sputum sampling.

Main Results:

• Microbial community structure and diversity in sputum are increasingly linked to COPD severity and clinical outcomes.
• Current evidence primarily comes from cross-sectional 16S rRNA studies, answering 'who is there?'.
• Advanced techniques like whole-genome sequencing and metabolomics can address functional aspects ('what can they do?' and 'what are they doing?').

Conclusions:

• The sputum microbiome is associated with COPD but requires further longitudinal study with standardized methods.
• Advanced sequencing and metabolomics offer deeper insights into microbial function in COPD.
• Future research should integrate multi-omics approaches for a comprehensive understanding of the COPD microbiome.