Sunday, 18 November 2018

Bacteria in the nose influence cold severity


Colds vary in their severity and for how long they last for. The reason is not solely down to the type of virus or the relative health of individuals. The bacterial population of the nose is also a factor, according to new research.

New research from University of Virginia Health System reveals that the bacteria found in the noses of test subjects fall into six different categories of nasal microbiomes. These varying patterns are associated with differences in cold virussymptom severity. Furthermore, the different microbial compositions link with the viral load level (that is the level of cold virus inside the body).

As an example of the variation, subjects whose noses were abundant with Staphylococcus bacteria tended to have more severe nasal symptoms compared with cold sufferers who carry a lower levels of such bacteria. This occurred even when subjects contracted colds of the same strain of virus.
The findings were based on a study of 152 people. The research did show, however, that there is no reverse effect. That is the microorganisms associated with people who tend to experience less severe colds are not 'beneficial', in that such bacteria could not be transferred to someone who experiences more severe colds in order to reduce the cold virus severity.

Commenting on this, lead scientist Dr. Ronald Turner stated: "The first surprise was that you can kind of identify these different buckets that people kind of fit into, and then the fact that the buckets seem to have some impact on how you respond to the virus and how sick you get was also interesting."

What is certain is that the bacteria around the nose do not cause the cold; what is less clear is how the nasal microbiome contributes to the relatively severity of the cold. Alternatively, it could be that the bacteria play no direct role at all but rather there is a characteristic that makes a person who is more likely to have higher levels of staphylococci in their nose also more likely to catch a cold and suffer 'worse' nasal symptoms. That is, there is a genetic characteristic shared by certain people which leads to the two factors being related. Whether there is an environmental dimension as well, such as an external trigger like pollution that affects both factors cannot yet to be determined.

The research is published in the journal Scientific Reports and it is titled "Nasal microbiota clusters associate with inflammatory response, viral load, and symptom severity in experimental rhinovirus challenge."
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

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