Interactions of Respiratory Viruses and the Nasal Microbiota during the First Year of Life in Healthy Infants

Abstract

Respiratory viral infections are very frequent in infancy and of importance in acute and chronic disease development. Infections with human rhinovirus (HRV) are, e.g., associated with the later development of asthma. We found that only symptomatic HRV infections were associated with acute changes in the nasal microbiota, mainly characterized by a loss of microbial diversity. Infants with more frequent symptomatic HRV infections had a lower bacterial diversity at the end of the first year of life. Whether the interaction between viruses and the microbiota is one pathway contributing to asthma development will be assessed in the follow-ups of these children. Independent of that, measurements of microbial diversity might represent a potential marker for risk of later lung disease or monitoring of early life interventions.

Haemophilus is overrepresented in the nasopharynx of infants hospitalized with RSV infection and associated with increased viral load and enhanced mucosal CXCL8 responses

“…This means that the number of different species reduces while there is no difference in the distribution of the numbers of each species. A reduced alpha diversity of the upper respiratory tract has also been shown in a longitudinal cohort study of symptomatic rhinovirus infections in infants (< 1 year) [31] and after administration of an intranasal live-attenuated influenza vaccine in adults [32]. Both studies were performed prospectively and show that lower alpha diversity is caused by viral infection and is not a prerequisite for viral infection.…”

Dysbiosis of the gut and lung microbiome has a role in asthma

“…It is of interest that the development of the resident respiratory microbiome depends very much on the exposure in the first few hours including delivery mode, and on the environment during the following 4 to 5 months [23][24][25]. A strong association was also observed between childhood asthma and respiratory infections, mainly induced by human rhinovirus and respiratory syncytial virus [26,27]. This is often accompanied by altered microbial spectra as shown in a mouse model of viral lung infection, resulting in an increase of phylum Bacteroidetes with a concomitant decrease in phylum Firmicutes [28].…”

The airway microbiota in early cystic fibrosis lung disease

“…In the first study, infants hospitalized with RSV ( n = 580) and HRV bronchiolitis ( n = 100) demonstrated increased abundance of Firmicute s ( Streptococcus ) and Proteobacteria ( Moraxella and Haemophilus ), respectively, while in the second study, Staphylococcus was increased in infants with RSV ( n = 83) and alpha‐diversity (within samples) was higher in those with HRV infection ( n = 52) . Conversely, a longitudinal study of 559 nasopharyngeal samples from 32 infants in the first year of life demonstrated that symptomatic HRV infection was associated with decreased alpha‐diversity and increased bacterial density (SDI 0.9 ± 0.7 vs 1.3 ± 0.9; mean polymerase chain reaction concentration 44 ± 35 ng/µL vs 29 ± 29 ng/µL, respectively), while frequent HRV infection was associated with reduced alpha‐diversity at the completion of the study (Shannon Diversity Index [SDI] coefficient −0.5 [95% CI −1.0 to 0.01]) . Lastly, in 106 infants with RSV infection compared with 26 healthy controls, dominance of Streptococcus or Haemophilus in the nasopharyngeal microbiota was positively associated, and Staphylococcus dominance inversely associated, with hospitalization .…”