A study has revealed that smoking cigarettes can alter throat microbiota and exacerbate influenza A virus infections. Smoking has long been recognized for its harmful effects on health, contributing to chronic pulmonary diseases and increasing the risk of influenza-related illnesses, among other conditions.
Recent research has explored the connection between cigarette smoke and changes in the oropharyngeal microbiota—the microbial community in the throat, including the soft palate, tonsils, and back of the tongue. While this link has been suspected, its exact nature was not fully understood until now.
Researchers at the University of Bern in Switzerland conducted a study using mice to examine how chronic cigarette smoke exposure affects both gut and throat microbiota. Markus Hilty, Associate Professor at the Institute for Infectious Diseases, explained that smoking alone does not directly cause respiratory disease. Instead, it is the altered microbiota in smokers that may influence the severity of respiratory infections, particularly viral ones like the flu.
In the study, mice exposed to cigarette smoke were housed with either air-exposed control mice or germ-free mice. This allowed researchers to transfer microbiota from the smoke-exposed or air-exposed mice to the germ-free mice.
The results, published in mSystems, a journal of the American Society for Microbiology, showed that germ-free mice colonized by bacteria from smoke-exposed mice had a more severe disease course when infected with the influenza A virus, including greater weight loss, compared to those colonized by bacteria from air-exposed mice.
Additionally, the infection led to substantial changes in the oropharyngeal microbiota, particularly on days 4 and 8 after infection.
Hilty urged physicians to consider the “cigarette-induced disordering of the microbiota” as a significant factor in the severity of viral infections, highlighting its potential impact on treatment and disease outcomes.
