Researchers at Seoul National University Hospital have found that respiratory mucosa contains good bacteria that could help human immunity functions, the hospital said Friday.

The team, led by Professor Kim Hyun-jik, came to the conclusions after investigating the symbiotic microbes distributed in the noses of 37 healthy adults from 2016 to 2017.

The researchers found that more than 3,000 symbiotic microorganisms were present in the nasal mucosa. After analyzing the symbiotic microorganisms, the team found that staphylococcus epidermidis, which was shown in 36 percent of them, is the most commonly found symbiotic microorganisms in the normal nasal mucosa.

Later, the researchers injected the staphylococcus epidermidis into the nasal mucosa of mice infected with influenza virus. The process reduced the virus by more than 90 percent, leading to increased resistance to influenza infection, while the mice that did not receive the staphylococcus epidermidis suffered from fatal lung infections.

The team further confirmed that the staphylococcus epidermidis, injected into the mice, stimulated the production of interferon lambda, which increases the expression of interferon-inducible genes and directly kills viruses, preventing the virus from multiplying.

The researchers hope that the study will become the basis in identifying the reasons for the presence of respiratory mucosal symbiotic microbes and develop a mucosal vaccine technology that will increase resistance for respiratory viruses, especially influenza virus-induced lung infection, the hospital said in a news release.

“It is the first research to prove that symbiotic microorganisms play an important role in digestion as well as respiration,” Professor Kim said. “The research also has great academic significance as it gave us an understanding of the triple interaction system, which is composed of the human immune system, symbiotic microorganism, and virus.”

The journal Microbiome published the results of the study.