Mycobiome analysis of electronic cigarettes reveals a reservoir of pathogenic yeasts

Research on the health impacts of e-cigarettes has focused on non-infectious manifestations. Given their enclosed plastic design and temperature fluctuations, we hypothesized that e-cigarettes are colonized by pathogenic microbes, thereby contributing to lung disease in users. Using sequencing and culture techniques of the devices and mouthwash of 25 users, we found only a small subset of mouthpieces to contain bacteria, whereas most were abundantly colonized with fungi that were distinct from the oral mycobiota, including the genera Rhodotorula, Aureobasidium, Cystobasidium, and Meyerozyma. Chronic exposure to the most frequently isolated pathogen, Cystobasidium minutum, resulted in mucus hypersecretion and obstructive lung disease in mice, characteristics of chronic bronchitis. We conclude that e-cigarettes are frequently colonized with fungal organisms capable of causing lung disease.