Antibiotics are used to fight bacterial infections, and unless there is a risk that a viral infection will lead to more problems, antibiotics are not often recommended for other illnesses. However, a new study has suggestd that a general antibiotic called neomycin could help prevent viral infections in the respiratory system, when the antibiotic is applied topically to the inside of the nose. The researchers determined that the antibiotic application activated interferon-stimulated genes (ISGs), causing an immune response in an animal model and healthy humans. The findings have been reported in the Proceedings of the National Academy of Sciences (PNAS).
"This is an exciting finding, that a cheap, over-the-counter, antibiotic ointment can stimulate the human body to activate an antiviral response," said co-senior study author Akiko Iwasaki, a Professor at Yale School of Medicine and Howard Hughes Medical Institute investigator.
In this work, mice that were exposed to either the SARS-CoV-2 virus or a virulent strain of influenza A were also given neomycin intranasally. A strong ISG response was triggered in both cases. Contact transmission of SARS-CoV-2 (the virus that causes COVID-19) was reduced in a hamster model that was treated intranasally with neomycin as well.
"Our work supports both preventative and therapeutic actions of neomycin against viral diseases in animal models, and shows effective blocking of infection and transmission," said Iwasaki.
There are often few drugs to reliably and effectively treat viral infections. They are typically monoclonal antibodies or plasma therapies, which can be expensive. But the application of a topical antibiotic may be a new and inexpensive way to prevent respiratory infections before they happen.
"Our findings suggest that we might be able to optimize this cheap and generic antibiotic to prevent viral diseases and their spread in human populations, especially in global communities with limited resources," Iwasaki said. "This approach, because it is host-directed, should work no matter what the virus is."
The researchers also confirmed these findings in a small group of people. When Neosporin, which contains Neomycin, was applied to healthy human noses, ISGs were strongly activated in some of the volunteers. However, this work will have to be confirmed in a larger cohort before a recommendation can be reliably made that people should use antibiotic ointment in their noses to prevent viral infections.
Sources: Yale University, Proceedings of the National Academy of Sciences
