The DuPont Microbiome Venture and Global Health & Nutrition Science teams have worked in collaboration with the University of Virginia and 4Pharma in an experimental rhinovirus challenge to understand the role of nasal microbiota clusters and their association with inflammatory response, viral load and symptom severity.
The study has been published recently in Scientific Reports.
In the clinical study, the nasal microbiota of the healthy adult study subjects was characterised before they were infected with the common cold virus.
The study team found that the baseline nasal microbiota samples divided into six types named after predominant bacterial genera:
- Staphylococcus
- Corynebacterium/Alloiococcus
- Moraxella
- Haemophilus
- Pseudomonadaceae/mixed
- Mixed.
Thus, each study subject could be classified based on nasal microbiota type before the infection.
The most common nasal microbiota types were Staphyloccocus, Corynebacterium/Alloiococcus, Moraxella and Pseudomonadaceae/mixed and these were used to compare differences in the course of the infection and severity of cold symptoms.
The investigators collected nasal washes during the course of the infection and analysed them for inflammatory markers and viral load.
Each nasal microbiota type had a characteristic inflammatory response and viral load profile. In general, subjects having Staphyloccocus, and Corynebacterium/Alloiococcus types had lower inflammatory responses and Pseudomonadaceae/mixed type had lower viral load than other types.
These results suggest that nasal microbiota influences the host response to rhinovirus infection. Importantly, changes in the response were reflected in cold symptoms and showed that subjects with Corynebacterium/Alloiococcus nasal microbiota type had lower symptom scores than Staphylococcus or Pseudomonadaceae/mixed types.
Overall the results of the study suggest a role for the nasal microbiota in the modulation of immune response, viral load and symptoms of the common cold in otherwise healthy adults.
Rhinoviruses are the predominant cause of the common cold and associated symptoms. Billions of rhinovirus infections occur each year and cause great discomfort for global populations along with loss in productivity for the world economy.
Current scientific literature indicates that changes in the nasal microbiota during infection or associations between the microbial profile and clinical characteristics can be detected when nasopharyngeal microbiota is characterised at the genus level.
Further research studies are required to fully elucidate the possibilities that changes in nasal microbiota could bring to the treatment of the common cold. However, this study raises the possibility that the modulation of the nasal microbiota might provide a positive intervention in rhinovirus-associated illness or other viral infections.