Lower respiratory tract microbiome composition and community interactions in smokers

Area of Science:

• Microbiology
• Pulmonology
• Environmental Health

Background:

• The lung microbiome plays a crucial role in lung function.
• Smoking is known to induce significant changes in the lower respiratory tract (LRT) microbiome.
• Understanding these smoking-induced alterations is vital for respiratory health.

Purpose of the Study:

• To explore complex co-occurrence and co-avoidance patterns in the LRT microbiome of active (AS), former (FS), and never smokers (NS).
• To identify differentially abundant taxa and potential biomarkers associated with smoking status.
• To assess the impact of smoking cessation on lung microbiota composition.

Main Methods:

• Collected bronchoalveolar lavages (BALs) from 55 subjects (9 NS, 24 FS, 22 AS).
• Assessed LRT microbiome composition using 16S rRNA amplicon sequencing.
• Employed discriminant analysis (Partial Least Square Discriminant Analysis, LEfSe) and DESeq2 for compositional analysis and biomarker identification.

Main Results:

• Smoking led to a loss of LRT microbiome diversity and a weakening of community structure.
• Distinct compositional differences were observed between never, former, and active smokers.
• The genus *Ralstonia* was significantly increased in both former and active smokers; smoking status biomarkers were identified.

Conclusions:

• Smoking profoundly alters the lung microbiome's diversity and structure.
• The lung microbiota composition differs significantly between smokers and non-smokers.
• Smoking cessation may not be sufficient for the lung microbiota to fully revert to a never-smoker state.