A recent study reveals that changes to the microbiota caused by cigarette smoke lead to worse outcomes in mice infected with the influenza A virus.
According to new findings, cigarette smoke can disrupt the oropharyngeal microbiota, worsening the impact of influenza A virus infections. This research has been published in mSystems, a journal associated with the American Society for Microbiology.
It has long been established that smoking is detrimental to health and linked to various respiratory illnesses. Cigarette smoke contributes to chronic pulmonary diseases and heightens the risk of illnesses related to influenza. More recently, studies have demonstrated a connection between cigarette smoke and changes in the composition of the oropharyngeal microbiota. However, the significance of these changes has not been fully understood. The oropharynx consists of the soft palate, walls of the throat, tonsils, and the rear of the tongue.
In this latest research, scientists discovered that chronic exposure to cigarette smoke alters both gut and oropharyngeal microbiota in mice. To separate the effects of smoking from those of the altered microbiota, they exposed one group of mice to cigarette smoke and housed them with another group exposed to clean air (acting as control) alongside germ-free mice. This setup enabled the transfer of microbiota from the donor mice to the germ-free ones. The germ-free mice were then colonized with bacteria from either smoke-exposed or air-exposed donors before being infected with the influenza A virus to observe the progression of the disease.
The findings revealed that germ-free mice that received bacteria from smoke-exposed mice experienced a more severe disease progression, shown by greater weight loss. Moreover, significant changes in the oropharyngeal microbiota composition were identified in connection with the viral infection, particularly noticeable on days 4 and 8 following the infection. This study design effectively differentiated the effects of the altered microbiota from the immune-modulating impacts of direct cigarette smoke exposure.
“It’s not just the act of smoking itself that influences respiratory diseases; our findings suggest that the microbiota of smokers may also play a role in respiratory conditions and infections. In our study, it particularly influenced viral infections,” stated Markus Hilty, Ph.D., the lead author and associate professor at the Institute for Infectious Diseases at the University of Bern in Switzerland. “The disruptions in microbiota caused by smoking are likely significant factors to consider during viral infections.”
