DuPont Nutrition & Health-led study uncovers nasal microbiota's role in host response to viral respiratory infection

26 Sep 2018 --- Nasal microbiota may influence the viral load, host innate immune response and clinical symptoms during rhinovirus infection, according to a collaborative clinical study between DuPont Nutrition & Health, the University of Virginia and 4Pharma Ltd. The researchers of these organizations worked in collaboration in an experimental rhinovirus challenge to understand the role of nasal microbiota clusters and their association with inflammatory response, viral load and symptom severity.

In the clinical study, published recently in Scientific Reports, the nasal microbiota of the healthy adult study subjects was characterized before they were infected with common cold virus.

The study team found that the baseline nasal microbiota samples divided into six types named after predominant bacterial genera: (1) Staphylococcus, (2) Corynebacterium/Alloiococcus, (3) Moraxella, (4) Haemophilus, (5) Pseudomonadaceae/Mixed, and (6) 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 over the course of the infection and analyzed 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.

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 characterized 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.

The DuPont Microbiome Venture team continue to work collaboratively with appropriate external partners to help advance our knowledge of important human microbiomes and to provide practical and science-based solutions for improvements in global health.