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Experimental endocarditis induction and platelet aggregation by Streptococcus anginosus, Streptococcus constellatus
1Department of Preventive Dentistry, Kagoshima University Dental School, Japan.
FEMS Immunology and Medical Microbiology
|October 10, 1997
Summary
Streptococcus anginosus strains are more likely to cause infective endocarditis and bacteremia in rats than other Streptococcus milleri group species. This suggests S. anginosus may be a more significant pathogen in endocarditis.
Area of Science:
- Microbiology
- Infectious Diseases
- Cardiovascular Research
Background:
- The Streptococcus milleri group comprises several species, including Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius, known to cause various infections.
- Infective endocarditis is a serious infection of the heart valves, often caused by bacteria.
- Understanding the specific pathogenic potential of different Streptococcus species is crucial for effective treatment and prevention.
Purpose of the Study:
- To compare the ability of different Streptococcus milleri group strains to induce infective endocarditis in a rat model.
- To investigate the correlation between bacterial load in vegetations and infectivity.
- To explore the relationship between platelet aggregation and endocardial infectivity.
Main Methods:
- Comparison of 18 Streptococcus milleri group strains, including type strains of S. anginosus, S. constellatus, and S. intermedius, against Streptococcus oralis.
- Induction of infective endocarditis in catheterized rats via intravenous injection of 10(8) colony-forming units.
- Assessment of vegetation formation, bacteremia, and microbial cell numbers in vegetations.
Main Results:
- All 8 tested S. anginosus strains induced infective vegetations and bacteremia in nearly all rats.
- S. constellatus and S. oralis strains showed lower frequencies of inducing vegetations and bacteremia.
- S. intermedius strains only occasionally caused infective endocarditis, and microbial cell numbers were highest in S. anginosus-infected vegetations.
Conclusions:
- Streptococcus anginosus demonstrates a significantly higher capacity to induce infective endocarditis and bacteremia compared to other Streptococcus milleri group species tested.
- No strong correlation was observed between the infective potential and platelet-aggregating capacity of these strains.
- Further research may elucidate specific virulence factors contributing to S. anginosus's pathogenicity in endocarditis.