Millares, LauraPascual Guàrdia, Sergi, 1979-Montón, ConcepciónGarcía-Nuñez, MarianLalmolda, CristinaFaner, RosaCasadevall Fusté, CarmeSetó, LaiaCapilla, SilviaMoreno, AmàliaCastro-Acosta, Ady AngélicaAlvarez-Martinez, Carlos JoséSibila, OriolPeces-Barba Romero, GermánCosio, Borja G.Agustí García-Navarro, ÀlvarGea Guiral, JoaquimMonsó Molas, Eduard2019-09-062019-09-062019Millares L, Pascual S, Montón C, García-Núñez M, Lalmolda C, Faner R et al. Relationship between the respiratory microbiome and the severity of airflow limitation, history of exacerbations and circulating eosinophils in COPD patients. BMC Pulm Med. 2019;19(1):112. DOI: 10.1186/s12890-019-0867-x1471-2466http://hdl.handle.net/10230/42250Background: The respiratory microbiome is altered in COPD patients but its relationship with core components of the disease, such as the severity of airflow limitation, the frequency of exacerbations or the circulating levels of eosinophils, is unclear. Methods: Cross-sectional study comprising 72 clinically stable COPD patients (mean age 68 [SD 7.9] years; FEV1 48.7 [SD 20.1]% of reference) who provided spontaneous sputum samples for 16S rRNA gene amplification and sequencing. The microbiome composition was analysed with QIIME. Results: We observed that: (1) more severe airflow limitation was associated with reduced relative abundance (RA) of Treponema and an increase in Pseudomonas; (2) patients with ≥2 exacerbations the previous year showed a significantly different bacterial community with respect to non-exacerbators (p = 0.014), with changes in 13 genera, including an increase of Pseudomonas, and finally, (3) peripheral eosinophils levels ≥2% were associated with more diverse microbiome [Chao1 224.51 (74.88) vs 277.39 (78.92) p = 0.006; Shannon 3.94 (1.05) vs 4.54 (1.06) p = 0.020], and a significant increase in the RAs of 20 genera. Conclusion: The respiratory microbiome in clinically stable COPD patients varies significantly according to the severity of airflow limitation, previous history of exacerbations and circulating eosinophils levels.application/pdfeng© The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.info:eu-repo/semantics/articlehttp://dx.doi.org/10.1186/s12890-019-0867-xBacterial communityDiversityEosinophilsExacerbationsSputumStable COPDinfo:eu-repo/semantics/openAccess