Researchers examined the microbiota of 27 people aged 49 to 78 years who were virus-negative, 30 who were positive but asymptomatic, and 27 who were moderately symptomatic and did not require hospitalization, and found a clear pattern. Have appeared, they report. Journal diagnosis.
“Millions of people are infected and a relatively small number are symptomatic, which may be one of the reasons,” said Dr. Ravindrakorge, director of the Georgia Esoteric Molecular Institute or GEM Institute at MCG. Says. Over 100,000 COVID tests have been performed.
The most important change was in symptomatic patients, with about half of the patients not having enough microbiota to perform the sequence, the corresponding author Fruzele said.
They were surprised to find these “low readings” of bacteria in the nasopharyngeal cavity of symptomatic individuals, whereas only 2 and 4 individuals in the asymptomatic group were negative and positive, respectively. .. The majority of asymptomatic positives still had a sufficient microbial flora, says lead author Kolhe.
“I don’t know which one came first, was sick, or was the removal of the microbiota,” says Fruzele. A runny nose and sneezing can be the cause of the loss, and the number of bacterial inhabitants has already dropped significantly, which may increase the risk for individuals to develop these types of symptoms.
Based on the experience of microbiota in the gastrointestinal tract, Kolhe considers the content and size of different microbiota to be another good bet, both hoping for a definitive answer. “We don’t have enough data at this time,” says Kolhe.
They found that there were differences in the types of bacteria, but researchers say that some of the functions of the bacteria they found are not well understood.
As the name of the virus and nearly two years of experience indicate, the main way to infect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2) is when someone coughs, sneezes, or talks. Is to do. The virus travels through the air and invades the nose and mouth of others.
People over the age of 65 and / or in basic health conditions such as high blood pressure and diabetes are considered to be at increased risk of death from hospitalization and infection, so the microbial flora in the upper part of the respiratory system called the nasopharynx I decided to investigate. senior citizen.
The lining of moist mucus production in this area acts like a natural barrier to invaders, there are also important complements of immune cells, and their response to respiratory viruses is important, says Frusele. ..
The area is also rich in ACE-2 receptors to which the spiky virus binds, and Kolhe states that it is the major landing site for the virus.
Their new findings indicate that altered microbiota in symptomatic patients affected their immune response to the virus, says Kolhe and Fulzele.
Symptomatic individuals have significantly higher levels of two bacterial species, including cutibacterium, commonly found on the skin and associated with acne, but also associated with postoperative heart and shoulder infections. Had had. Conversely, the presence of a small number of other under-researched bacteria was significantly lower.
The microflora of both symptomatic and asymptomatic infected groups had high levels of bacteria, such as cyanobacteria, also known as cyanobacteria. It is found in polluted water, but it is a normal habitat for the human microflora and appears to play a role in regulation. Immune response.
These bacteria are known to enter the body through mucosal surfaces such as the nose, causing pneumonia and liver damage. Symptomatic individuals had twice as much of this bacterium as asymptomatic individuals.
Does Fulzele state that there was no significant change in microbial flora diversity between asymptomatic and symptomatic? Only a big difference in volume ?? But they saw many individual bacteria move up and down in numbers.
For example, a graph of the number of another water-loving bacterium, Amylibacter, looked like a staircase as it changed from negative to positive in symptomatic individuals, but tended to decline in some other bacteria. ..
The relationship between nasopharyngeal microbial flora and COVID-19 severity remains unclear, but their study shows a “strong association” between nasal microbial flora, SARS-CoV-2 infection and severity. They write.
Their analysis was done before the current viral variants began to surface, but researchers say that differences in microbial flora are likely to apply to these as well and have already begun their analysis. ing.
Researchers say larger studies are needed to ensure that the clear patterns they find are preserved. They have put together a grant application that allows them to do larger research and find other test sites they want to partner with. They say that the same nasopharyngeal swabs used for many COVID tests can be used to perform microbiota analysis at the same time as the test.
They point to a striking contrast revealed by nearly two years of experience with the virus, where the majority of infected people are asymptomatic or experience mild symptoms such as the common cold, but others. People develop severe viral pneumonia, require hospitalization, and die.
Several recent studies have been published suggesting that the bacterial composition of the nasal cavity can have a “dramatic” effect on the development and severity of respiratory infections, they write.
Some studies have shown that the nasal microflora can affect the viral load, immune response, and symptoms of rhinovirus infection, which is responsible for 10-40% of common colds. increase.
They write that a myriad of other conditions, such as inflammatory bowel syndrome, gastric ulcer, and Wils disease, are associated with significant changes in the gut, nasal, and oral microflora.
Bacterial diversity in microbiota is generally good, according to Frusere, which naturally decreases with age and is ameliorated by habits such as smoking and by eating a variety of diets. There is also the possibility of doing so.
This work was partially supported by the National Institutes of Health.