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Isolation and Characterization of Extracellular Vesicles Produced by Iron-limited Mycobacteria
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Functional characteristics of membrane vesicles produced by Streptococcus mitis
Airi Matsumoto1, Yuichi Oogai1,1, Haruka Kurashige1,2,1
1Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Journal of Oral Microbiology
|September 26, 2025
Summary
Mitis group streptococci (MGS) produce membrane vesicles (MVs) that modulate host immune responses and inhibit pathogenic bacterial biofilms. These MVs are crucial for MGS survival and pathogenicity in oral infections.
Area of Science:
- Microbiology
- Bacteriology
- Oral Biology
Background:
- Mitis group streptococci (MGS) are primary oral bacteria linked to bacteremia and infective endocarditis.
- Limited research exists on membrane vesicle (MV) production across diverse MGS species.
Purpose of the Study:
- To investigate MV production in various MGS species.
- To characterize the biological functions of MGS-derived MVs.
Main Methods:
- MVs were isolated from MGS cultures via density gradient ultracentrifugation.
- MV protein content was analyzed using liquid-chromatography tandem mass spectrometry.
- Effects of MVs on host cells and oral pathogens were assessed.
Main Results:
- MV production was confirmed in *Streptococcus mitis* strains, with particle sizes of 100-120 nm.
- MVs were internalized by epithelial cells and modulated cytokine production in macrophages and neutrophils.
- MVs suppressed biofilm formation in *Aggregatibacter actinomycetemcomitans*.
Conclusions:
- MGS-derived MVs are vital for bacterial survival strategies.
- MVs contribute to MGS pathogenicity through immune modulation and interspecies competition.
- MVs play a significant role in host-pathogen interactions within the oral microbiome.
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