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Updated: Sep 9, 2025
Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels
Published on: August 7, 2017
Insights into the relationship between nasal bacterial composition and susceptibility to early-life respiratory
Jose A Caparrós-Martín1,2,3, Elizabeth Kicic-Starcevich3, Patricia Agudelo-Romero3,4,5
1UWA Medical School, UWA Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia.
Insights
The nasal microbiota may influence infant wheezing in a sex-specific way. This pilot study explored early-life nasal microbial communities and their link to respiratory illnesses in infants.
Area of Science:
- Microbiology
- Pediatric Respiratory Medicine
- Immunology
Background:
- Early-life viral respiratory infections are linked to long-term childhood respiratory issues.
- Predictive tools for infant respiratory infection susceptibility are currently lacking.
- The endogenous microbiota is a potential target for preventing respiratory infections due to its role in pathogen virulence and airway inflammation.
Purpose of the Study:
- To investigate the association between distinct nasal microbial communities and viral respiratory disease in infants.
- To explore the relationship between nasal microbiota and respiratory phenotypes during the first year of life.
Main Methods:
- Analysis of 90 nasal swabs from 55 infants in the AERIAL study (background and symptomatic samples).
- Bacterial profiling using full-length 16S rRNA sequencing.
- Quantification of bacterial load via pan-bacterial TaqMan® assay.
Main Results:
- Nasal bacterial diversity was similar between background and symptomatic swabs; composition varied by individual.
- Symptomatic swabs showed reduced diversity but unchanged bacterial load.
- Two distinct bacterial endotypes (Moraxella- or Streptococcus-enriched) were identified, differing in alpha diversity.
- Virus-bacteria interactions were noted in rhinovirus-positive swabs, but not SARS-CoV-2-positive swabs.
- No association found between background microbial endotypes and symptomatic episodes or bronchiolitis.
- A potential sex-specific association between endotypes and wheezing episodes was observed.
Conclusions:
- Pilot data suggest the nasal microbiota may influence wheezing outcomes in a sex-specific manner.
- Larger, longitudinal studies are needed to confirm these findings and explore the role of the nasal microbiota in infant respiratory health.
Background:
Early-life susceptibility to viral respiratory infections is associated with long-term respiratory morbidity in children. Currently, no reliable tools exist to predict susceptibility to these infections. Given its role in modulating pathogen virulence and airway inflammation, the endogenous microbiota represents a potential target for prevention. In this pilot study, we investigated whether distinct nasal microbial communities are associated with viral respiratory disease and respiratory phenotypes during the first year of life.
Methods:
We analyzed 90 nasal swabs from 55 infants enrolled in the AERIAL study, representing background samples collected at schedule visits (~4 months old) and samples from symptomatic episodes. Bacterial profiling was done blinded to clinical data via full-length 16S rRNA sequencing, and bacterial load was quantified using a pan-bacterial TaqMan® assay.
Results:
Nasal bacterial diversity was similar between background and symptomatic swabs, with community composition differences largely driven by inter-individual variation. In paired samples, symptomatic swabs showed reduced diversity but no change in bacterial load. Virus-bacteria interactions were observed in rhinovirus-positive swabs, but not in SARS-CoV-2-positive swabs. Two distinct bacterial endotypes were identified, enriched in either Moraxella or Streptococcus species and differing in alpha diversity. In background swabs, microbial endotypes were not associated with the number of symptomatic swabs or bronchiolitis episodes. We observed a potential sex-specific association between background swabs endotypes and number of wheezing episodes, which warrants further investigation in follow-up studies.
Conclusion:
Our pilot data suggest that the nasal microbiota might influence wheezing outcomes in a sex-specific manner, highlighting the need for larger, longitudinal investigations.
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