Airway microbiota in children with bronchial mucus plugs caused by Mycoplasma pneumoniae pneumonia

There is increasing evidence for a role of lung microbiota in the pathogenesis of Mycoplasma pneumoniae pneumonia (MPP). However, the alterations of lung microbiota in MPP with bronchial mucus plugs and its role in disease pathogenesis remain poorly understood. In this prospective observational study, we performed a longitudinal 16S rRNA-based microbiome survey on bronchoalveolar lavage (BAL) samples collected from 31 MPP with bronchial mucus plugs and 52 MPP without mucus plugs. Our study showed a clear difference in airway microbiota between MPP children with and without bronchial mucus plugs. The MPP children with mucus plugs had lower abundances of Sphingomonas and Elizabethkingia, and a high abundance of Mycoplasma compared with MPP children without mucus plugs, subsequently contributing to increased ratios of Mycoplasma to Sphingomonas and Mycoplasma to Elizabethkingia. Children's age, fever time and serum cytokine levels were associated with airway microbiota alteration. Furthermore, significant correlations between bacterial genus abundances were found in MPP children with mucus plugs. Our results suggest an impact of airway microbiota on the clinical course of MPP in children, deserving further investigations. •Lung microbiota plays a role in the pathogenesis of Mycoplasma pneumoniae pneumonia (MPP).•The children with MPP and bronchial mucus plugs had lower abundances of Sphingomonas and Elizabethkingia.•Airway microbiota had an impact on the clinical course of children with Mycoplasma pneumoniae pneumonia.