Objective： To analyze the differences in the types and quantity of bacterial colonization in the upper respiratory tract between the children with asthma and the healthy children. Methods: Eight preschool children with asthma admitted to our hospital from October 2020 to October 2021 were selected, and 18 healthy children who underwent physical examination in our hospital during the same period were selected as the control group. The differences in the species and quantity of respiratory flora between the two groups were analyzed. Results: 16S rDNA sequencing showed that the species abundences and diversity of the upper respiratory tract microbiota in children with asthma increased, and the structure of the microbiota changed significantly. The total number of amplicon sequence variants （ASVs） in the asthma group and the control group was 375, and the unique ASVs were 889 and 1 037, respectively. The asthma group had significant changes in ASVs compared with the control group. At the phylum level, the asthma group had a significant reduction in the relative abundance of Firmicutes (P<0.01) and significant increases in the relative abundance of Actinobacteria, Fusobacteria, and Campilobacterota (P<0.05). At the genus level, the asthma group had a significant reduction in the relative abundance of Streptococcus and Sphingomonas (P<0.05) and a significant increase in the relative abundance of Neisseria (all P<0.05). Conclusion: There are significant differences in the types and quantity of bacterial flora in the upper respiratory tract between children with asthma and healthy children, and the children with asthma have a state of respiratory flora disorder.
［Key words］asthma; children; upper respiratory tract bacteria; bacterial diversity; 16S rDNA sequencing