Children with asthma who had nasal airway microbiota populations dominated by Moraxella had increased exacerbation risk and eosinophil activation, according to the results of a study published in the Journal of Allergy and Clinical Immunology.

Nasal secretion samples were collected during the fall season from children aged 6 to 17 years with asthma who were enrolled in a trial of omalizumab. 16S rRNA profiling was performed to determine dominate nasal airway microbiota populations. Correlations between dominate nasal airway microbiota populations and clinical outcomes were assessed. The primary outcome was the rate of exacerbation; rates of rhinovirus infection and respiratory illnesses were secondary outcomes. 

Among the 3122 nasal secretion samples collected from 413 children with asthma, 6 nasal airway microbiota assemblages were observed. Each assemblage was dominated by a different species: Moraxella, Staphylococcus, Corynebacterium, Streptococcus, Alloiococcus, or Haemophilus. Nasal microbiota dominated by Moraxella was associated with increased exacerbation risk and eosinophil activation, while Staphylococcus– or Corynebacterium-dominated microbiota were associated with reduced respiratory illness and exacerbation events.

“Our data form a foundation for more in-depth investigations to determine how distinct nasal airway microbiomes, and more specifically, active members of these assemblages, interact with the host mucosa to promote or protect from exacerbations in children with asthma,” the researchers wrote. “Moreover, microbiome-based identification of children with asthma at heightened risk for exacerbation could lead to targeted strategies to promote appropriate nasal airway mucosal colonization and potentially reduce exacerbation risk.”

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Reference

McCauley K, Durack J, Valladares R, et al; for the NIAD-sponsored Inner-City Asthma Consortium. Distinct nasal airway bacterial microbiota differentially relate to exacerbation in pediatric asthma [published online June 12, 2019]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2019.05.035