Why some people get worse colds than others

 Your natural nose bacteria could be an issue, study reveals - paving the way to individualized treatments

The organisms that live inside your nose could determine the type and severity of the cold symptoms you develop, a new study has found.

Researchers say that people with more bacteria in their noses that causes lower respiratory tract infections, food poisoning and boils are also more likely to cough and sneeze when they get the common cold.

 Past evidence has shown that the bacteria found in the gut can influence innate immune responses, according to Daily Mail.

The team from the University of Virginia School of Medicine says their findings shed fresh light on the elusive common cold and could pave the way to individualized treatments for the virus.

For the study, the team looked at the nasal microbiome of 152 participants both before and after injecting them with rhinovirus type 39, a common cold virus.

This was to confirm the collection of bacteria wouldn't be greatly altered after they got sick.

To analyze the microbiome, researchers took nasal swabs and stool samples and evaluated them - and symptoms - over the next five days. 

The team found that the nasal bacteria could fall into one of six patterns - and symptom severity depended on which the pattern the volunteer had.

The pattern was also associated with viral load, or the amount rhinovirus in the body. 

Findings showed that cold sufferers whose noses had a great deal of Staphylococcus bacteria had more severe nasal symptoms than those with less staph.

This bacteria can cause boils, food poisoning, impetigo and toxic shock syndrome.  

In addition, those with more Moraxella - which causes lowers respiratory tract infections - also had worse symptoms and a greater viral load.

These differences in symptoms were despite the fact that the participants' colds were caused by the same viral strain.

Researchers admitted they were surprised by their discovery.

'The first surprise was that you can kind of identify these different buckets that people kind of fit into,' said Dr Ronald Turner, a professor of pediatrics at the University of Virginia School of Medicine.

'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,'  

'So the background microbiome, the background bacterial pattern in your nose, had influences on the way that you reacted to the virus and how sick you got.'

In addition, the team wanted to see if giving the participants probiotics, or good bacteria, would alleviate their cold symptoms or change the makeup of their nasal microbiomes.

All the participants were given a liquid probiotic to drink, but it did not affect the bacteria in the participants' noses or in their stomachs.

Dr Turner said it's possible that a nasal spray probiotic might be more effective, but that would require further research.  

'It's not going to be so simple, I don't think, as saying: "OK, what happens if you give a probiotic?"' he said. 

'One of the things that would be interesting to ask, and this would be a completely different study, is, what happens if you give antibiotics? 

'Can you change the nasal flora by giving antibiotic? And is that a good thing or is that a bad thing? Those are all unknowns.' 

He added that more research is also needed to determine the exact link between the nasal microbiome and the severity of cold symptoms.

'What we're reporting is an association, so it's entirely possible that the fact that you have staph in your nose and you have more symptoms is not directly related,' Dr Turner said.

'It may well be that there's some underlying host characteristic that makes you likely to have staph in your nose and also makes you more likely to become ill.'  

This means that a person's genes could be responsible for the makeup of nasal bacteria and symptom severity.

Dr Turner said there could also be environmental elements that are at play. 

'Whether you're exposed to pollution or whether you're allergic or whether any number of things might impact it, I don't know,' he said. 

'But I suspect there is some interaction among the host and the environment and the pathogen that determines what you end up with.' 

N.H.Kh

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