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Updated: Jul 18, 2026
09:26
Identification of Antibacterial Immunity Proteins in Escherichia coli using MALDI-TOF-TOF-MS/MS and Top-Down Proteomic Analysis
Published on: May 23, 2021
Toxin-antitoxin systems are ubiquitous and plasmid-encoded in vancomycin-resistant enterococci
Elizabeth M Moritz1, Paul J Hergenrother
1Department of Microbiology, Roger Adams Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Summary
Vancomycin-resistant enterococci (VRE) harbor the mazEF toxin-antitoxin system on their plasmids, which is essential for VRE survival. Targeting this system offers a novel therapeutic strategy against VRE infections.
Area of Science:
- Microbiology
- Molecular Biology
- Antimicrobial Resistance
Background:
- Vancomycin-resistant enterococci (VRE) are significant hospital-acquired infections.
- VRE infections are increasing, with over 25% of ICU cases showing vancomycin resistance.
- Mechanisms of VRE plasmid maintenance and novel therapeutic targets are needed.
Purpose of the Study:
- To identify novel protein targets for VRE treatment.
- To investigate the role of toxin-antitoxin (TA) gene systems in VRE plasmid stability.
Main Methods:
- Screening of plasmids from 75 VRE isolates for TA gene systems.
- Detection of the mazEF system and its co-localization with the vanA gene.
- Plasmid stability assays and RT-PCR to assess mazEF functionality.
Main Results:
- The mazEF TA system was found in 100% of VRE isolates examined.
- MazEF genes were located on the same plasmid as the vanA gene in over 90% of cases.
- Evidence suggests plasmid-encoded mazEF is functional in VRE.
Conclusions:
- The mazEF system is ubiquitous in VRE and may play a role in plasmid stability.
- Disrupting the mazEF system presents a promising strategy for developing new VRE antimicrobial therapies.
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