Related Experiment Video

Updated: Apr 16, 2026

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii
10:24

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii

Published on: April 10, 2020

14.5K

Outer membrane vesicles isolated from two clinical Acinetobacter baumannii strains exhibit different toxicity and

Zhi-Tao Li1, Rui-Ling Zhang1, Xiao-Gang Bi1

  • 1Department of Intensive Care Unit, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510530, Guangdong, China.

Microbial Pathogenesis
|March 17, 2015
PubMed

Insights

Multidrug-resistant Acinetobacter baumannii produces more outer membrane vesicles (OMVs) containing greater virulence factors. These OMVs exhibit enhanced cytotoxicity and trigger stronger immune responses, contributing to worse clinical outcomes.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Immunology

Background:

  • Outer membrane vesicles (OMVs) are key virulence factors in Gram-negative bacteria.
  • Acinetobacter baumannii is an opportunistic pathogen often associated with multidrug resistance.
  • Understanding OMV production and composition is crucial for deciphering bacterial virulence.

Purpose of the Study:

  • To compare OMV production and virulence between a multidrug-resistant (MDRAb) and a non-multidrug-resistant strain of Acinetobacter baumannii.
  • To investigate the impact of OMVs on host cell cytotoxicity and innate immune responses.
  • To identify specific virulence factors within OMVs from the MDRAb strain.

Main Methods:

  • Isolation and quantification of OMVs from two clinical Acinetobacter baumannii strains (MDRAb A38 and non-MDRAb 5806).
  • Cell proliferation assays and real-time PCR to assess cytotoxicity and innate immune responses.
  • SDS-PAGE and LC-MS/MS analysis to identify protein components of OMVs.

Main Results:

  • The MDRAb strain (A38) produced significantly more OMVs than the non-MDRAb strain (5806).
  • OMVs from A38 induced higher cytotoxicity and stronger innate immune responses compared to 5806 OMVs.
  • A38 OMVs were enriched with virulence factors including Omp38, EpsA, Ptk, GroEL, hemagglutinin-like protein, and FilF.

Conclusions:

  • Abundant OMV production in MDRAb strains may contribute to increased virulence.
  • The specific composition of OMVs, rich in virulence factors, likely drives enhanced pathogenicity.
  • Further research is warranted to explore the role of these OMV factors in Acinetobacter baumannii infections.
Keywords:
Acinetobacter baumanniiInnate immunityOuter membrane vesiclesProteomicsVirulence

More Related Videos

Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System05:06

Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System

Published on: January 5, 2024

1.2K
Size Exclusion Chromatography to Analyze Bacterial Outer Membrane Vesicle Heterogeneity07:26

Size Exclusion Chromatography to Analyze Bacterial Outer Membrane Vesicle Heterogeneity

Published on: March 31, 2021

5.6K

Related Concept Videos

Bacterial Toxins01:12

Bacterial Toxins

Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
95
Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
15.5K
Intralumenal Vesicles and Multivesicular Bodies01:38

Intralumenal Vesicles and Multivesicular Bodies

Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
5.3K
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
57
Export of Misfolded Proteins out of the ER01:32

Export of Misfolded Proteins out of the ER

After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
5.7K