Oral Presentation Australia and New Zealand Society for Extracellular Vesicles Conference 2025

Salivary Bacterial and Fungal Extracellular Vesicles in Oral Inflammatory Disease Pathogenesis (127149)

Chun Liu 1 , Jenny Wang 1 , Andrew Lai 2 , Carlos Salomon 2 , Jayampath Seneviratne 1 , Sašo Ivanovski 1 , Pingping Han 1
  1. The University of Queensland School of Dentistry, Herston, QLD, Australia
  2. The University of Queensland, Brisbane, QLD, Australia

Introduction

Salivary microbial extracellular vesicles (EVs), released by bacteria and fungi, are key mediators of host–microbe communication. Unlike whole microbes, these nanoscale vesicles can cross epithelial barriers, deliver virulence factors and modulate immune responses. Isolating microbial EVs (both bacteria and fungi sources) from saliva provides a non-invasive approach to study oral-systemic inflammation and offers potential for biomarker discovery.

Methods

This cross-sectional study collected unstimulated whole saliva from 20 healthy individuals and 57 patients with periodontitis. Host-derived EVs were first isolated from saliva using an immunoaffinity method. Subsequently, microbial-derived EVs were enriched from the remaining supernatant via size exclusion chromatography (SEC) and analyzed by 16S rRNA gene and ITS sequencing.

Results

16S sequencing revealed that salivary bacterial EVs from periodontitis patients were significantly enriched with pathogenic bacterial genera compared to healthy controls, particularly Gram-negative outer membrane vesicles (OMVs) producing taxa such as Tannerella (P=0.0006), Treponema (P=0.0006), and Porphyromonas (P=0.0363) (Figure 1), as well as membrane vesicles (MVs) from the Gram-positive genus Filifactor (P<0.0001). 18S ITS sequencing data demonstrated that a marked increase in fungal EVs from Candida (P<0.0001) and Trichosporon (P<0.0001) in periodontitis patients.

Conclusion

Both bacterial and fungal EVs are involved in oral inflammation through enrichment of key pathogens and hold potential as diagnostic biomarkers for oral and systemic inflammatory diseases.

 

  1. Kim, H.Y., et al., Extracellular vesicles derived from the periodontal pathogen Filifactor alocis induce systemic bone loss through Toll‐like receptor 2. Journal of extracellular vesicles, 2021. 10(12): p. e12157.
  2. Brown L, Wolf JM, Prados-Rosales R, Casadevall A. Through the wall: extracellular vesicles in Gram-positive bacteria, mycobacteria and fungi. Nature Reviews Microbiology. 2015 Oct;13(10):620-30.