Different clinical feature among asthmatics according to airway microbiome clusters

RATIONALE: Asthma is a heterogeneous disease with chronic airway inflammation and previously reported several studies showed the alterations of microbiota in airway of asthma patients. We focused on changes in microbiome of induced sputum from asthma patients with combined clinical factors.

METHODS: Induced whole sputum of 20 healthy adult subjects and 86 adult asthmatics were obtained. The V3-4 hypervariable region of the bacterial 16S rRNA gene was amplified. Bacterial DNA library data were prepared by sequencing amplicons with the MiSeq v3 platform (Illumina®). Data sets were cleaned and analyzed using QIIME and Ezbiocloud 16S database. Cluster dendrogram was constructed using weighted UniFrac distance data. Chi-square test or Kruskal-Wallis rank sum test was used for analyzing categorical or continuous variables, respectively.

RESULTS: When clustering into two groups (1 and 2) based on UniFrac method, the proportion of several clinical variables were significantly different between groups; high dose inhaled corticosteroid (ICS) (41.2% vs 20.8%, p = 0.043), antibiotics use within six months (35.3% vs 8.3%, p = 0.002), chronic rhinosinusitis (CRS) (55.9% vs 20.8%, p = 0.0007), nasal polyps (17.6% vs 1.4%, p = 0.006). While group 1 had dominancy of Streptococcus, group 2 showed abundant Prevotella. Group 2 showed relatively longer duration of asthma (11.15 years vs. 6.38 years, p = 0.002) and lower asthma control test score (16.5 vs. 19.9, p = 0.045).

CONCLUSIONS: Clinical variables such as the use of high dose ICS, antibiotics use, CRS, duration of asthma, and asthma control seems to be related with characteristics of airway microbiota.