title: Corticosteroid therapy and airflow obstruction influence the bronchial microbiome, which is distinct from that of bronchoalveolar lavage in asthmatic airways.
abstract: The lung has a diverse microbiome that is modest in biomass. This microbiome differs in asthmatic patients compared with control subjects, but the effects of clinical characteristics on the microbial community composition and structure are not clear.
  
  
  
  We examined whether the composition and structure of the lower airway microbiome correlated with clinical characteristics of chronic persistent asthma, including airflow obstruction, use of corticosteroid medications, and presence of airway eosinophilia.
  
  
  
  DNA was extracted from endobronchial brushings and bronchoalveolar lavage fluid collected from 39 asthmatic patients and 19 control subjects, along with negative control samples. 16S rRNA V4 amplicon sequencing was used to compare the relative abundance of bacterial genera with clinical characteristics.
  
  
  
  Differential feature selection analysis revealed significant differences in microbial diversity between brush and lavage samples from asthmatic patients and control subjects. Lactobacillus, Pseudomonas, and Rickettsia species were significantly enriched in samples from asthmatic patients, whereas Prevotella, Streptococcus, and Veillonella species were enriched in brush samples from control subjects. Generalized linear models on brush samples demonstrated oral corticosteroid use as an important factor affecting the relative abundance of the taxa that were significantly enriched in asthmatic patients. In addition, bacterial α-diversity in brush samples from asthmatic patients was correlated with FEV1 and the proportion of lavage eosinophils.
  
  
  
  The diversity and composition of the bronchial airway microbiome of asthmatic patients is distinct from that of nonasthmatic control subjects and influenced by worsening airflow obstruction and corticosteroid use.
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Darcy R
authors.initials: DR
authors.lastname: Denner
authors.affiliation: Biosciences Division (BIO), Argonne National Laboratory, Argonne, Ill.
authors.forename: Naseer
authors.initials: N
authors.lastname: Sangwan
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Julia B
authors.initials: JB
authors.lastname: Becker
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: D Kyle
authors.initials: DK
authors.lastname: Hogarth
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Justin
authors.initials: J
authors.lastname: Oldham
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Jamee
authors.initials: J
authors.lastname: Castillo
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Anne I
authors.initials: AI
authors.lastname: Sperling
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Julian
authors.initials: J
authors.lastname: Solway
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Naureckas
authors.affiliation: Biosciences Division (BIO), Argonne National Laboratory, Argonne, Ill; Departments of Ecology & Evolution and Surgery, University of Chicago, Chicago, Ill; Institute for Genetics, Genomics, and Systems Biology, University of Chicago, Chicago, Ill; Marine Biological Laboratory, Woods Hole, Mass.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Gilbert
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Ill. Electronic address: swhite@bsd.uchicago.edu.
authors.forename: Steven R
authors.initials: SR
authors.lastname: White
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000382:microbiology* / Q000503:physiopathology; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D001980:Bronchi / Q000382:microbiology*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D004802:Eosinophilia / Q000382:microbiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D064307:Microbiota; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D000305:Adrenal Cortex Hormones; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: 16S ribosomal RNA; Asthma; FEV(1); bacteria; corticosteroids; microbiome