Respiratory microbiota diversity and composition in recurrent protracted bacterial bronchitis: a cross-sectional study.

Introduction: Recurrent protracted bacterial bronchitis (RPBB) is a significant risk factor for bronchiectasis in children, characterized by multiple episodes of protracted bacterial bronchitis (PBB) annually. With an increasing global incidence, a detailed understanding of RPBB's pathophysiology is essential, particularly regarding the role of lung microbiota.

Methods: This cross-sectional study recruited 39 children from Jinhua Maternal and Child Health Hospital between January 2021 and December 2022, including 18 with PBB, 11 with RPBB, and 10 as controls. Bronchoscopy with bronchoalveolar lavage (BAL) was performed to collect lung microbiota samples, which were analyzed using 16S rDNA sequencing. Microbial diversity and composition differences among groups were assessed using alpha and beta diversity metrics, PERMANOVA, and Linear Discriminant Analysis Effect Size (LEfSe), with statistical significance set at < 0.05.

Results: RPBB patients exhibited a distinct lung microbiota composition compared to controls, characterized by an increased abundance of pathogens such as and , alongside a reduction in beneficial genera like and . The RPBB group also demonstrated greater overall microbiota diversity, indicating dysbiosis that may contribute to disease severity and persistent respiratory symptoms.

Conclusion: This study revealed significant alterations in the lung microbiota of children with RPBB, suggesting that microbial imbalance could play a crucial role in disease pathogenesis. These findings highlight the importance of targeted prevention and therapeutic strategies aimed at restoring microbiota balance to improve pediatric respiratory health.