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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
The Spx regulator modulates stress responses and virulence in Enterococcus faecalis
Jessica K Kajfasz1, Jorge E Mendoza, Anthony O Gaca
1Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, USA.
Infection and Immunity
|April 18, 2012
Summary
The Spx regulator is crucial for Enterococcus faecalis to survive oxidative stress and cause infections. Deleting spx impairs bacterial growth, increases susceptibility to stress, and reduces virulence in mouse models.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Enterococcus faecalis is an opportunistic pathogen causing hospital-acquired infections.
- Coping with reactive oxygen species (ROS) is a key virulence factor for E. faecalis.
- The role of global regulators in oxidative stress tolerance and virulence is not fully understood.
Purpose of the Study:
- To identify and characterize the function of the Spx global regulator in E. faecalis.
- To investigate the role of Spx in oxidative stress tolerance and virulence.
- To understand the regulatory network controlled by Spx.
Main Methods:
- In silico analysis to identify the Spx regulator.
- Construction and characterization of a Δspx mutant strain.
- Assessment of growth under various stress conditions (aerobic, oxidative, antibiotic).
- Evaluation of virulence in a murine peritonitis model.
- Transcriptional analysis to identify Spx-regulated genes.
Main Results:
- The Δspx mutant showed impaired growth under aerobic conditions and sensitivity to oxidative stress agents.
- The mutant strain was also susceptible to antibiotic stress and macrophage killing.
- Virulence in a mouse model was significantly reduced for the Δspx strain.
- Transcriptional analysis indicated Spx positively regulates numerous oxidative stress genes.
Conclusions:
- Spx is a major global regulator of stress response genes in E. faecalis.
- Spx plays a critical role in oxidative stress tolerance and bacterial virulence.
- Spx is implicated in the pathophysiology of E. faecalis infections.
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