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Updated: Jan 9, 2026
Scalable Isolation and Purification of Extracellular Vesicles from Escherichia coli and Other Bacteria
Published on: October 13, 2021
Membrane Vesicles from Lacticaseibacillus Casei BL23 Exhibit Antimicrobial Activity Against Escherichia coli and
Cecilia L D'Antoni1,2,3, Leila Pourtalebi Jahromi3, Lorenzo Sana3
1Departamento De Química Biológica De La Facultad de Ciencias Exactas y Naturales Universidad De Buenos Aires, Buenos Aires, Argentina.
Abstract:
Probiotics are live microorganisms known for their health benefits; however, they may pose risks for immunocompromised individuals. This study explores the potential of postbiotics, specifically membrane vesicles (MVs) derived from Lacticaseibacillus casei BL23, as a safer alternative. MVs are isolated via ultracentrifugation (UC) followed by size exclusion chromatography (SEC), revealing a mean size of 178 nm and a concentration of 2.53×1011 particles mL-1, with moderate stability over four months at 4°C. Antimicrobial assays demonstrate that SEC-isolated MVs effectively inhibit the growth of Escherichia coli DH5α. Confocal laser scanning microscopy confirms the internalization of MVs by both E. coli and macrophages. Additionally, MV treatment elicits a significant immune response, marked by increased levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-8, IL-1β) alongside IL-10 production in peripheral blood mononuclear cells. Importantly, cytotoxicity assays indicate that MVs are non-toxic to these cells and preserve epithelial barrier integrity in Caco-2 cell monolayers. MVs showed a trend towards extending lifespan in the Caenorhabditis elegans in vivo model upon infection with Pseudomonas aeruginosa. These findings underscore the dual-activity potential of L. casei BL23 MVs as effective tools for combating infections while enhancing immune function, offering a promising strategy to address antibiotic resistance.
Insights
Postbiotics like Lacticaseibacillus casei BL23 membrane vesicles (MVs) offer a safer alternative to probiotics. These MVs combat E. coli infections and stimulate immune responses without toxicity.
Area of Science:
- Microbiology
- Immunology
- Biotechnology
Background:
- Probiotics offer health benefits but pose risks to immunocompromised individuals.
- Postbiotics, such as membrane vesicles (MVs), are explored as safer alternatives.
- Lacticaseibacillus casei BL23-derived MVs are investigated for their therapeutic potential.
Purpose of the Study:
- To evaluate the safety and efficacy of L. casei BL23 MVs as a postbiotic.
- To assess the antimicrobial activity, immune-modulating effects, and safety profile of these MVs.
- To explore their potential in an in vivo model of infection.
Main Methods:
- Isolation of MVs using ultracentrifugation and size exclusion chromatography.
- Antimicrobial assays against Escherichia coli DH5α.
- Confocal microscopy for cellular internalization studies.
- Cytokine analysis in peripheral blood mononuclear cells.
- Cytotoxicity assays and epithelial barrier integrity tests.
- In vivo lifespan studies in Caenorhabditis elegans.
Main Results:
- SEC-isolated MVs exhibited antimicrobial activity against E. coli.
- MVs were internalized by E. coli and macrophages.
- MV treatment induced significant pro-inflammatory and IL-10 cytokine responses.
- MVs demonstrated no cytotoxicity and preserved epithelial barrier integrity.
- A trend towards extended lifespan was observed in C. elegans infected with Pseudomonas aeruginosa.
Conclusions:
- L. casei BL23 MVs possess dual activity, combating infections and modulating immune responses.
- These MVs represent a promising, safe alternative to probiotics for therapeutic applications.
- The findings support the potential of MVs in addressing antibiotic resistance and enhancing host immunity.
