Airway microbiome clusters and heterogeneous interactions of microbial communities in adult asthma

Microbiome has been emerged as one of the hidden players regulating asthma. However, the association between microbiome dysbiosis and asthma morbidity is not consistent and often failed to replicate. Further, changes in microbial interactions within communities have not been properly validated in asthma. To characterize airway microbiome communities reflecting the clinical features of asthma. Sputum microbiome profiles from 155 participants composed of normal control and asthmatic patients were compared according to clinical severity and clusters classified by hierarchy based on the abundance of microbes. Alpha and beta diversities of the airway microbiome were not significantly altered by the presence of asthma or its severity. The proportions of Fusobacterium and Rothia were increased and those of JN713389_g and Saccharimonas were decreased in the non-severe asthma compared to control group (FDR < 0.1). However, the microbiome composition did not differ according to the clinical severity of asthma. Three clusters (C1, C2, and C3) based on the microbial abundance showed significant differences in ‘weekly salbutamol use’, ‘oral corticosteroid use within 6 months’, and ‘nighttime asthma symptom’ (p-value = 0.009, 0.007, and 0.045, respectively). Microbial interactions of each cluster were heterogeneous; C1, a cluster with less asthma attacks, showed positive interactions within the microbiome community while C2 and C3, clusters with more asthma attacks, presented multiple negative interactions presenting competitive relationship. The microbiome in asthmatic airways did not show apparent differences according to clinical severity, but clustering based on microbial abundance revealed difference in microbial interactions as well as clinical features.