Harmful Fungi Found on Vape Mouthpieces, Study Reveals

A new study has revealed that the mouthpieces of e-cigarettes used by daily vapers can be “abundantly colonized” with an array of fungi, some of which have been linked to lung complications. The research highlights a previously under-explored risk associated with vaping, shifting focus from the chemical constituents of e-liquids to the microbial contaminants that may be inhaled from the devices themselves.

While vaping is generally recommended by public health bodies as a less harmful way for adult smokers to transition away from combustible cigarettes, its long-term health impacts remain poorly understood. This new study, conducted by researchers at the University of Florida, sought to understand which microbes might be making their way from vaping devices into users’ airways.

To investigate, the team, led by Borna Mehrad, recruited 25 people who used disposable vapes every day. They cultured the microbes found on the mouthpieces of their devices and compared them to the microbes present in the volunteers’ mouths. While only a small number of the vapes contained significant bacteria, the results for fungi were striking. More than half of the devices were heavily colonized with fungal species that were distinct from those found in the users’ own mouths, and an alarming 80% of these identified fungi are capable of causing illness in people.

The most common species found was Cystobasidium minutum, which has previously been linked to blood infections in people with suppressed immune systems. To test its potential impact on respiratory health, the research team had mice inhale C. minutum, mimicking the entry method of vaping. “We found that the fungus that was most prevalent in the vape samples caused features of chronic bronchitis in mice,” stated Mehrad. This condition involves inflammation of the airways and can cause persistent flu-like symptoms.

The source of these fungi is not yet certain. Some are present in the air or on our hands, but team member Jason Smith suggested they might have already been present in the vape liquids when purchased, or that “the residues left behind inside the vape device may provide a food source for moulds to grow.” Team member Katy Deitz noted she wasn’t surprised by the findings, given that most participants – about a third of whom reported respiratory symptoms like coughing – did not clean their vapes.

Ian Musgrave, an expert at the University of Adelaide in Australia who was not involved in the study, found the research interesting. He noted that fungi have also been found in shisha (hookahs), which has been linked to microbial-induced lung disease. “What is interesting is that the microbiota found in this study were dominated by potentially pathogenic fungi, which are rare in the mouth microbiome,” he said.

However, Musgrave also stressed a crucial caveat: there isn’t yet enough evidence to conclude that these fungal species exist in high enough numbers on vape mouthpieces to cause ill health in humans. He recommends that vapes should be cleaned regularly as a precaution. The study underscores that while vaping avoids many harms of smoking, it is not without its own potential risks, and further research is needed to fully understand the long-term effects of inhaling these microbial contaminants.