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Brucella stationary-phase gene expression and virulence.
R Martin Roop1, Jason M Gee, Gregory T Robertson
1Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, North Carolina 27858-4354, USA. roopr@mail.ecu.edu
Annual Review of Microbiology
|May 6, 2003
Summary
Host factor I (HF-I) is crucial for Brucella spp. survival within macrophages. This protein regulates stationary-phase physiology, essential for chronic infection and intracellular persistence.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Host-Pathogen Interactions
Background:
- Brucella spp. establish chronic infections by residing in host macrophages.
- Long-term intracellular survival depends on bacterial adaptation to the phagosomal environment.
- Host factor I (HF-I) is an RNA-binding protein involved in bacterial stress response and gene regulation.
Purpose of the Study:
- To investigate the role of the hfq gene, encoding HF-I, in Brucella spp. pathogenesis.
- To determine the importance of stationary-phase physiology for Brucella's intracellular survival and virulence.
Main Methods:
- Construction and in vitro characterization of a Brucella abortus hfq mutant.
- Assessment of mutant survival and replication in cultured murine macrophages.
- In vivo virulence studies using experimentally infected animals (mice).
Main Results:
- The B. abortus hfq mutant exhibited defects in stationary-phase physiology.
- The hfq mutant showed reduced survival and replication in macrophages compared to wild-type.
- Both B. abortus and B. melitensis hfq mutants were significantly attenuated in vivo.
Conclusions:
- Stationary-phase physiology, regulated by HF-I, is essential for Brucella's ability to establish and maintain long-term intracellular residence.
- HF-I-regulated genes likely contribute to Brucella's resistance to harsh phagosomal conditions.
- The hfq gene is critical for Brucella virulence and chronic infection potential.