Multiple respiratory microbiota profiles are associated with lower airway inflammation in children with protracted bacterial bronchitis.

Neutrophilic inflammation in children with PBB was associated with multiple BAL microbiota profiles. Significant associations between inflammatory markers and bacterial biomass, but not alpha diversity, suggest that inflammation in children with PBB is not driven by single pathogenic species. Understanding the role of the entire respiratory microbiota in PBB pathogenesis may be important to determining whether bacteria other than the recognized pathogens contribute to disease recurrence and progression to bronchiectasis.