While marketers promote e-cigarettes as a safer alternative to tobacco products, research from Ohio State University suggests that their risks to subgingival microbiota may be similar to or greater than smoking. The investigation examined subgingival plaque samples from 100 periodontally and systemically healthy individuals.
The subjects were divided into 5 groups: e-cigarette users (E), cigarette smokers (S), dual users (SE), former smokers currently using e-cigarettes (FSE), and controls (NSNE). The researchers used whole genome shotgun-sequencing for functional and taxonomic characterization. They also validated the findings using an in vitro biofilm model.
The researchers found that 8,879 functionally annotated genes were identified in the e-cigarette microbiome, with more than one-third of which were found in all individuals in the E, SE, and FSE groups. By contrast, subjects in the S and NSNE groups shared a maximum of 15% of their genes.
The e-cigarette users were functionally and taxonomically distinct from both smokers and nonsmokers. Also, 1,353 genes were unique to the E, SE, and FSE groups, encoding for antibiotic resistance, motility-chemotaxis, stress response, horizontal gene transfer, cell wall, iron acquisition, and membrane transport.
Several known pathogens belonging to the genera Fusobacteria, Treponema, Prevotella, and Bacteroides, as well as several as yet uncultivated species, encoded these functionalities. The E, SE, and FSE groups were compositionally and functionally similar. These differences in functional potential also were evident at the transcriptional level. And, the researchers identified 51 biomarkers of e-cigarette exposure.
The researchers, then, concluded that the risk for harm associated with e-cigarettes may be similar to or greater than smoking. The similarity in the microbiomes of former, current, or never smokers who use e-cigarettes does not support the hypothesis that e-cigarettes promote harm reduction in cigarette smokers. The pathogen and virulence enrichment observed in clinically healthy individuals might augur the emergence of a new risk factor for periodontal diseases, the researchers said.
The study, “Electronic Cigarettes Exacerbate Virulence Potential in the Disease-Naïve Subgingival Microbiome,” was presented at the 95th General Session & Exhibition of the International Association for Dental Research in San Francisco in March.