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Host-pathogen interactions in bacterial endocarditis: streptococcal virulence in the host
M C Herzberg1, M W Meyer, A Kiliç
1Department of Preventive Sciences, School of Dentistry, University of Minnesota, Minneapolis 55455, USA.
Advances in Dental Research
|April 1, 1997
Summary
Researchers identified streptococcal genes activated during experimental endocarditis using a novel reporter plasmid. These findings suggest specific Streptococcus gordonii genes contribute to virulence in this condition.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Bacterial endocarditis is a serious infection, often caused by Streptococcus species.
- Understanding gene expression during infection is crucial for identifying virulence factors.
Purpose of the Study:
- To identify genes in Streptococcus gordonii that are expressed during experimental endocarditis.
- To investigate the genetic basis of S. gordonii virulence in a host model.
Main Methods:
- Development of a promoter-less dual reporter gene-fusion plasmid (pAK36) for identifying expressed genes.
- Construction of a random gene fusion library from S. gordonii V288 chromosomal DNA.
- Inoculation of the library into rabbits to induce experimental endocarditis, followed by positive selection and screening of surviving clones.
Main Results:
- Isolation and screening of clones from valvular vegetations after chloramphenicol treatment.
- Identification of at least 13 distinct S. gordonii genes induced during experimental endocarditis.
- Analysis of gene insertions using Southern hybridization confirmed differential gene expression.
Conclusions:
- Specific Streptococcus gordonii genes are induced during experimental endocarditis.
- These induced genes likely play a role in the pathogenesis and virulence of S. gordonii infections.
- The developed reporter system is effective for identifying host-induced genes in bacterial pathogens.