Relationship between the respiratory microbiome and systemic patterns in COPD

Objective: To evaluate the relationships between respiratory microbiome and main COPD phenotyes Methods: Sputum samples from COPD patients were obtained during stability and 16S rRNA gene was analyzed. Taxonomic and diversity information were correlated with frequent exacerbator (FE) and eosinophilic COPD (EC) phenotypes Results: 78 subjects were analyzed, mean age 67 (SD 9) years. Patients with ≥2 exacerbations the previous year were considered FE (n=23). Their bacterial community was significantly different (p=0.014) from patients with no exacerbations (n=31), with changes in RA of 3 phyla and 13 genera, which included an increase in Pseudomonas. Patients with 1 exacerbation (n=18) showed borderline differences in their bacterial community (p=0.081) compared to no exacerbations patients, with a loss of RA of 2 phyla and 13 genera. Patients with 1 or ≥2 exacerbations showed similar borderline differences (p=0.087) with changes in RA of 4 genera. EC patients, identified by a systemic eosinophil level ≥2%, showed a significantly more diverse respiratory microbiome [Chao1 224.5 (74.9) vs 280.5 (79.6) p=0.003; Shannon 3.9 (1.1) vs 4.6 (1.1) p= 0.010] and a different community structure (p=0.037), mediated by a significant increment of 4 phyla and 26 genera Conclusion: A specific bacterial composition was shown in stability samples of FE and EC phenotypes. The presence of 1 exacerbation the previous year produces significant changes in the RA of specific OTUs and in patients with ≥2 exacerbations these changes lead to significant differences in their bacterial community. The respiratory microbiome was more diverse in EC patients and with a specific bacterial community Funded by FIS 15/00167, SEPAR and BRN-Pla Armengol