Airway Microbiota Profiles in Children With and Without Asthma: A Comparative Study

Background: Asthma is a common chronic respiratory disease that affects children and adults and can have a serious impact on their quality of life. Factors contributing to the development of asthma and related exacerbations are multifactorial, with microbial communities colonizing the airways possibly playing a key role. Methods: The study included asthmatic (79) and healthy children (57) aged 5–16 years. Nasal and throat swabs were collected, and bacterial (16s rRNA) and fungal (18s rRNA) amplicon sequence analysis was performed. Diversity indices and the most abundant microbial genera were estimated accordingly. Results: At the level of the bacteriome in the nasal samples, the asthma group had significantly lower diversity than the control group (p = 0.02). However, the microbiota of the asthma cohort was more evenly distributed, and staphylococci were enriched in the control group. Throat samples collected from the asthma cohort revealed significantly lower diversity (p < 0.0001), with a significant difference in species composition between the two groups (p = 0.005). Enriched bacterial species were different within the asthma subgroups (controlled vs uncontrolled asthma). The fungal microbiome of the nasal and throat samples showed no difference in species richness between the two groups, however, a significant difference in beta diversity (species composition) was detected. The nasal samples from the control group were enriched with Malassezia species, while the asthma cases were enriched with Mucor species. On the other hand, throat specimens of the asthma group were found to be enriched with Candida and Saccharomyces. Conclusion: Our findings suggest that asthmatic samples were less diverse than the control samples with certain microbial genera enriching some study groups. Addressing the biomarkers that influence the progression of asthma could lead to improved care for children suffering from severe asthmatic episodes, possibly by including targeted therapies and prevention strategies.