Variations in fecal microbial profiles of acute exacerbations and stable chronic obstructive pulmonary disease

Aim: Alterations in the respiratory and digestive tract microbiomes influence the occurrence and progression of chronic obstructive pulmonary disease (COPD). Here, we aimed to identify fecal microbiome profiles during COPD development. Methods: Fecal samples were collected from 29 COPD patients with acute exacerbation (AECOPD), 29 stable COPD patients, and 22 normal subjects (NS). The fecal microbial profiles were obtained using 16S rRNA gene sequencing. Key findings: The diversity and richness were lower and fewer variations in the taxonomic composition of fecal microbiota were observed in AECOPD patients than in stable COPD and NS. The relative abundances of Firmi-cutes and Actinobacteria were decreased, while those of Bacteroidetes and Proteobacteria were increased in AECOPD compared to COPD and NS. Among the top ten genera, the proportions of Lachnoclostridium and Parabacteroides significantly increased in AECOPD, whereas those of other genera decreased. Discriminative bacteria, such as p_Bacteroidetes, c_Bacteroidia, o_Bacteroidales, Lactobacillales, and Proteobacteria, were identified in AECOPD compared to stable COPD and NS. The weighted gene co-expression networks showed that Firmicutes and Actinobacteria were the main hub bacterial taxa related with lung function (FEV1% and FEV1/FVC%) and inflammatory indices (TNF-alpha, IL-6, IL-8, PCT, and CRP). Significance: These findings emphasized the changes in the abundance and composition of the fecal microbiome in stable COPD and AECOPD. Variations in fecal microbiota may be associated with COPD progression.