# Influence of E-Liquids and Oral Commensal Bacteria on the Growth of Porphyromonas gingivalis Planktonically and in Biofilms

## TL;DR

This study explores how e-liquids and oral bacteria affect the growth of a harmful mouth bacterium linked to periodontal disease.

## Contribution

The novel finding is that e-liquids increase the growth of Porphyromonas gingivalis in multispecies oral biofilms despite inhibiting it in planktonic conditions.

## Key findings

- E-liquids inhibit planktonic growth of P. gingivalis but are partially counteracted by commensal bacterial supernatants.
- E-liquids enhance P. gingivalis growth in multispecies biofilms, suggesting a risk for oral dysbiosis in vapers.
- Findings indicate that vaping may alter oral microbial communities, potentially increasing periodontal disease risk.

## Abstract

Background: The increasing use of electronic cigarettes (ECIGs), especially among youth, has raised concerns about the impact of vaping on oral health. While ECIGs are often marketed as a safer alternative, the existing literature suggests that their use may have detrimental effects on the pulmonary and cardiovascular systems. The oral cavity is the first point of contact for ECIG aerosol, and new reports link vaping to the onset of periodontal disease. It is critical to understand the potential effects of vaping on the oral microbiome, which affects systemic health. This study investigates how flavored E-liquids and commensal bacteria influence the growth of Porphyromonas gingivalis, a periodontal pathobiont, under planktonic and biofilm conditions. Methods: P. gingivalis was grown planktonically in the presence of the supernatants of four streptococcal species (Streptococcus gordonii, Streptococcus intermedius, Streptococcus mitis, and Streptococcus oralis) and flavored E-liquids (tobacco, menthol, cinnamon, strawberry, and blueberry) under anaerobic conditions. Multispecies biofilms, including all the species mentioned above and Fusobacterium nucleatum, were also grown anaerobically and quantified by crystal violet assays, qPCR, and CFU counts. Results: Although E-liquids inhibit P. gingivalis growth under planktonic conditions, the presence of commensal supernatants partially mitigates this effect. However, P. gingivalis growth in multispecies biofilms is increased by E-liquid treatments. Conclusions: This study highlights the enhanced growth of P. gingivalis as part of an oral microbial community in the presence of E-liquids. These results suggest that E-liquid-induced alterations in multispecies biofilms may contribute to the observed dysbiosis in vapers and the associated risk of oral diseases.