CHRONIC exposure to cigarette smoke (CS) may significantly worsen the severity of influenza A virus (IAV) infections, not only through direct lung damage but also via changes in the microbiota. New research highlights how CS-induced microbiota disruption in the respiratory tract and gut can amplify the severity of flu symptoms, suggesting that managing microbial health could be crucial for improving influenza outcomes in vulnerable populations.
The study used C57BL/6J mice, which were exposed to cigarette smoke for 5.5 months before being cohoused with germ-free mice to transfer the disrupted microbiota. These colonized mice were then infected with the H1N1 influenza A virus. Researchers observed significant differences in disease progression between the two groups. Mice colonized with CS-associated microbiota showed greater weight loss and more severe flu symptoms, with differences in microbiota composition becoming apparent as early as 4 days post-infection.
The Streptococcaceae bacterial family stood out as the primary microbiota difference between CS-exposed and control mice in the oropharynx. The study’s findings suggest that the microbiota shift caused by cigarette smoke exposure, even without direct lung damage, can increase the severity of respiratory infections like influenza A. Notably, the research points to the potential role of microbiota modulation in therapeutic strategies aimed at reducing flu severity, especially for individuals with a history of smoking.
Healthcare professionals should be aware of the emerging evidence linking cigarette smoke exposure with not just pulmonary diseases but also altered microbiota composition, which could affect patient response to infections such as influenza.
Reference: Wüthrich T et al. Cigarette smoke-induced disordered microbiota aggravates the severity of influenza A virus infection. mSystems. 2024;0:e00790-24.
