TY - JOUR T1 - Azithromycin alters spatial and temporal dynamics of airway microbiota in idiopathic pulmonary fibrosis JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00720-2022 VL - 9 IS - 3 SP - 00720-2022 AU - Pieter-Jan Gijs AU - Cécile Daccord AU - Eric Bernasconi AU - Martin Brutsche AU - Christian F. Clarenbach AU - Katrin Hostettler AU - Sabina A. Guler AU - Louis Mercier AU - Niki Ubags AU - Manuela Funke-Chambour AU - Christophe von Garnier Y1 - 2023/05/01 UR - http://openres.ersjournals.com/content/9/3/00720-2022.abstract N2 - Background High bacterial burden in the lung microbiota predicts progression of idiopathic pulmonary fibrosis (IPF). Azithromycin (AZT) is a macrolide antibiotic known to alter the lung microbiota in several chronic pulmonary diseases, and observational studies have shown a positive effect of AZT on mortality and hospitalisation rate in IPF. However, the effect of AZT on the lung microbiota in IPF remains unknown.Methods We sought to determine the impact of a 3-month course of AZT on the lung microbiota in IPF. We assessed sputum and oropharyngeal swab specimens from 24 adults with IPF included in a randomised controlled crossover trial of oral AZT 500 mg 3 times per week. 16S rRNA gene amplicon sequencing and quantitative PCR (qPCR) were performed to assess bacterial communities. Antibiotic resistance genes (ARGs) were assessed using real-time qPCR.Results AZT significantly decreased community diversity with a stronger and more persistent effect in the lower airways (sputum). AZT treatment altered the temporal kinetics of the upper (oropharyngeal swab) and lower airway microbiota, increasing community similarity between the two sites for 1 month after macrolide cessation. Patients with an increase in ARG carriage had lower bacterial density and enrichment of the genus Streptococcus. In contrast, patients with more stable ARG carriage had higher bacterial density and enrichment in Prevotella.Conclusions AZT caused sustained changes in the diversity and composition of the upper and lower airway microbiota in IPF, with effects on the temporal and spatial dynamics between the two sites.In IPF, azithromycin alters the dynamics of the microbiota between the upper and lower airways and community turnover over time, with a decrease in richness without impacting the bacterial density. https://bit.ly/3Jp9xOg ER -