title: Lower airway microbiota: COPD, stable and exacerbating
design: Bacterial DNA was extracted from induced sputum samples from COPD patients during periods of disease stability, and at the beginning and end of exacerbations of COPD symptoms using the Qiagen AllPrep DNA and RNA Mini kit on the QIAcube automation platform. 16S metagenomic sequencing was performed by 16S V3-V4 amplification followed by Illumina MiSeq paired-end sequencing using a 600 cycle version 3 cartridge.