Lower airway microbiome of children with recurrent wheezing: a clinical cohort study

BACKGROUND: Wheezing is one of the most common respiratory symptoms in childhood especially in infants. In recent years, the incidence of recurrent wheezing is on the rise worldwide. To investigate the lower airway microbiota in patients with recurrent wheezing and provide insights into clinical diagnosis and treatment. METHODS: This study initially enrolled 45 hospitalised children with recurrent wheezing symptoms awaiting complete fiberoptic bronchoscopy. Of these, 13 children with tracheobronchomalacia were excluded. The final population included 32 participants (group A). The control group comprised 23 children who inhaled a foreign body and were admitted to the hospital for fiberoptic bronchoscopy within 24 hours (group B). Deoxyribonucleic acid (DNA) was extracted from the bronchoalveolar lavage fluid (BALF) and amplified for the 16S ribosomal Ribonucleic Acid (rRNA) gene, and sequencing of the microbiome was performed using the Illumina Nova Seq 6000 system. RESULTS: There were significant differences in the gestational duration (P=0.0458), mode of delivery (P=0.0261), and allergy status (P=0.0000) between groups A and B, but they had similar richness (P=0.8574). There was also a marked difference in the diversity of flora composition between the two groups (P=0.0095). The three most common phyla of microbiota in the two groups were Proteobacteria, Firmicutes, and Bacteroidetes. Species with notably different phyla included Proteobacteria, Bacteroidota, Fusobacteriota, and Acidobacteriota. There was a significant enrichment in the of Proteobacteria and lower levels of Bacteroidota, Fusobacteriota, and Acidobacteriota in group A compared to that in group B. CONCLUSIONS: Significant changes occur in the lower airway microbiota during recurrent wheezing in children. The discovery of beneficial airway bacteria may facilitate the prevention and treatment of recurrent wheezing or asthma in children.