Four groups of distinct lung microbiota in pulmonary diseases
Bronchoalveolar lavage fluid (BALF) was collected and stored at -80Â°C DNA was extracted from BALF using the TIANamp  Micro DNA kit (DP316, Tiangen Biotech).  DNA libraries were constructed with the  end-repair method and then sequenced on the BGI Sequencer platform (BGI Genomics,  Shenzhen, China)