Microbiota associations with inflammatory pathways in asthma.

BACKGROUND

The airway microbiota plays an important role in asthma pathophysiology. However, the relationship between the airway microbiota and asthma phenotypes is still poorly understood.

OBJECTIVE

We aimed to characterize the airway microbiota in asthma patients and determine its correlation with airway inflammatory phenotypes and other phenotypic characteristics.

METHODS

The microbial composition of induced sputum specimens collected from asthma patients was determined using 16S rDNA gene sequencing.

RESULTS

Patients with asthma had a higher abundance of bacterial taxa associated with Bacteroidetes, Fusobacteria and Proteobacteria and a reduced abundance of Firmicutes and Actinobacteria compared to healthy controls. This study classified the asthma-associated lung microbiota into three community types based on DMM models, which were defined as three pulmotypes (P1, P2 and P3). The lungs of patients with pulmotype 3 (P3) were dominated by Faecalibacterium and Bacteroides, while patients with pulmotype 1 (P1) had a greater abundance of Pasteurellaceae, Streptococcus and Rothia. P1 patients were older (p = .045) and had lower blood TGF levels (p = .028). P3 patients had fewer eosinophils (p = .016) and more neutrophils (p = .039) in induced sputa than P1 patients.

CONCLUSIONS

Differences in asthma-associated airway microbiota pulmotypes are associated with and might influence asthma, particularly inflammatory phenotypes.