A decrease in microbial infection in adolescents is implicated with an increase in the incidence of asthma and allergic diseases in adulthood, indicating that the microbiome plays a critical role in asthma. However, the microbial composition of the lower respiratory tract remains unclear, hindering the further exploration of the pathogenesis of asthma. This study aims to explore the microbial distribution and composition in the lungs of normal rats and rats with allergic asthma via 16S rDNA sequencing.

The DNA of the pulmonary microbiome was extracted from the left lungs collected from normal control group (NC), saline control group (SC), and allergic asthma group (AA) under aseptic conditions. After the 16s rDNA V4eV5 region was amplified, the products were sequenced using Illumina high-throughput technology and subjected to operational taxonomic unit (OTU) cluster and taxonomy analysis.

The OTU values of AA increased significantly compared with those of NC and SC. Microbiome structure analysis showed that the dominant phylum of the pulmonary microbiome changed from Proteobacteria in NC to Firmicutes in AA. Linear discriminant analysis indicated that the key microbiomes involved in the three groups varied.

Numerous microbiomes stably settled in the lungs of the rats in NC and AA. The structure and diversity of the pulmonary microbiome in AA differed from those in NC.