Dynamics of the airway microbiome in response to exposure to particulate matter 2.5 in patients with chronic obstructive pulmonary disease

Background: Particulate matter (PM) and air pollution have been suggested to be associated with chronic obstructive pulmonary disease (COPD), contributing significantly to global respiratory disease-related mortality. This study aimed to investigate whether seasonal exposure to PM influences dysbiosis in the respiratory microbiota of patients with COPD. Methods: Sputum samples were collected four times over 1 year from 102 patients with COPD, and 16S rRNA sequencing was performed. The dynamics of the airway microbiota were analyzed depending on PM exposure levels and season. Results: The PM-low exposure group had higher α-diversity compared to the PM-high exposure group, particularly noted in spring. Some bacterial groups, including seven species such as Treponema socranskii, were more abundant in the low exposure group. Additionally, the bacterial community structure in summer significantly differed from that in other seasons, with significantly increased α-diversity in this season. The difference in the airway microbiome due to PM exposure was prominent in patients with moderate COPD. Conclusions: PM exposure may influence changes in the sputum microbiome depending on exposure levels and seasonal variations. Our results suggest that airway microbiomes could vary with PM exposure according to seasonal trends. © 2024 Elsevier B.V.