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Multicenter Study
. 2025 Jan:236:107906.
doi: 10.1016/j.rmed.2024.107906. Epub 2024 Dec 4.

Airway total bacterial density, microbiota community composition and relationship with clinical parameters in bronchiectasis

Zina Alfahl  1 , Gisli G Einarsson  2 , J Stuart Elborn  2 , Deirdre F Gilpin  1 , Katherine O'Neill  2 , Kathryn Ferguson  3 , Adam T Hill  4 , Michael R Loebinger  5 , Mary Carroll  6 , Timothy Gatheral  7 , Anthony De Soyza  8 , James D Chalmers  9 , Christopher Johnson  10 , John R Hurst  11 , Jeremy S Brown  11 , Judy M Bradley  2 , Michael M Tunney  12
Affiliations
Free article
Multicenter Study

Airway total bacterial density, microbiota community composition and relationship with clinical parameters in bronchiectasis

Zina Alfahl et al. Respir Med. 2025 Jan.
Free article

Abstract

Background and objective: This study explored the relationship between total bacterial density, airway microbiota composition and clinical parameters in bronchiectasis. We determined changes with time during clinical stability and following antibiotic treatment of a pulmonary exacerbation.

Methods: We conducted a multicentre longitudinal cohort study of UK participants with CT confirmed bronchiectasis. Sputum samples and clinical parameters [FEV1% predicted, lung clearance index, C-reactive protein, white cell count and Quality of Life] were collected when participants were clinically stable and pre/post-antibiotic treatment of an exacerbation. Total bacterial density and microbiota community composition was measured by quantitative polymerase chain reaction and sequencing of the V4 region of bacterial 16S rRNA, respectively.

Results: Among 105 participants at baseline, 65 (62 %) were female with a mean age of 65 years and FEV1 at 69 % predicted. In participants who remained clinically stable (n = 15), no significant changes were observed in bacterial density, microbiota diversity, richness, evenness, and dominance (p = 0.30, 0.45, 0.54, 0.23 and 0.43; respectively) across four time points over a 1-year period. Similarly, for participants with paired pre/post-antibiotic treatment samples (n = 19), no significant changes were observed (p = 0.30, 0.46, 0.44, 0.71 and 0.58; respectively). However, considerable fluctuation in community composition between samples was apparent for most patients. Total bacterial density and microbiota composition did not correlate with clinical parameters at baseline (n = 75).

Conclusions: Stability in bacterial density and microbiota diversity, richness, evenness and dominance was observed over time at a population level but considerable fluctuation was apparent in samples from individual patients.

Keywords: Bacterial density; Bronchiectasis; Clinical outcomes; Microbiome composition; Quality of life; Quantitative real time PCR.

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Conflict of interest statement

Declaration of competing interest Z.A, G.E., D.G., K.O., K.F., A.H., M.C., T.G., C.J., J.B.: no conflict of interest. J.S.E.: reports grants from European Union IMI Grant (in collaboration with Novartis) and grants from Novartis, and personal fees from Vertex, Galapagos and Ionis, outside the submitted work. M.L.: reports funding from by the Innovative Medicines Initiative (IMI) and EFPIA companies under the European Commission funded project, iABC (grant 115721). Consulting fees from Armata, 30T, Astra Zeneca, Parion, Insmed, Chiesi, Zambon, Electromed, Recode, AN2, Boehringer Ingelheim and Mannkind. Payment or honoraria for lectures by Insmed and Unpaid ERS infection group chair. A.D.S.: received grants from AstraZeneca, Pfizer, GSK and Novartis for research into Bronchiectasis and consulting fees from AstraZeneca, Insmed, GSK, Boehringer, 30T and Bayer. J.C.: received funding from Astrazeneca, Boehringer Ingelheim, Chiesi, Glaxosmithkline, Insmed, Novartis, Gilead Sciences, Trudell, Genentech and consulting fees from Astrazeneca Boehringer Ingelheim, Chiesi, Glaxosmithkline, Insmed, Novartis, Pfizer, Zambon, Janssen, Antabio. J.H.: received funding from Astra Zeneca and consulting fees from Astra Zeneca and GSK. Payment for honorary lectures from Astra Zeneca, Boehringer Ingelheim, Chiesi, Sanofi, Takeda and equipment from Nonin. J.M.B.: received funding Northern Ireland Clinical Research Facility, Health and Social Care (Northern Ireland) and the National Institute for Health and Care Research. M.M.T: received funding from the European Union Innovative Medicines Initiative (Grant Agreement number 115721), Novartis, Spexis and Antabio.

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