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In vitro resistance to thrombin-induced platelet microbicidal protein is associated with enhanced progression and
V K Dhawan1, A S Bayer, M R Yeaman
1Charles Drew University-Martin Luther King Medical Center, Los Angeles, California 90059, USA.
Abstract:
We examined the influence of thrombin-induced platelet microbicidal protein 1 (tPMP-1) on the progression and hematogenous dissemination of experimental endocarditis caused by isogenic Staphylococcus aureus strains differing in tPMP susceptibility (tPMPs) or resistance (tPMPr) in vitro. Following simultaneous challenge of animals with both strains, significantly higher tPMPr bacterial densities were present in vegetations (P < 0.0001), kidneys (P < 0. 0001), and spleens (P < 0.0001) compared with those for the tPMPs strain. These data indicate that tPMP-1 limits the intravegetation proliferation and hematogenous dissemination of a tPMPs strain in experimental endocarditis, while the tPMPr phenotype confers a selective advantage associated with the enhanced progression of this infection.
Insights
Thrombin-induced platelet microbicidal protein 1 (tPMP-1) limits Staphylococcus aureus growth in experimental endocarditis. Resistance to tPMP-1 provides a survival advantage, enhancing infection progression.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Staphylococcus aureus is a common cause of infective endocarditis.
- Thrombin-induced platelet microbicidal protein 1 (tPMP-1) is an antimicrobial peptide with a role in host defense.
- The role of tPMP-1 in endocarditis pathogenesis is not fully understood.
Purpose of the Study:
- To investigate the impact of tPMP-1 susceptibility on Staphylococcus aureus endocarditis progression.
- To determine if tPMP-1 influences bacterial dissemination in a murine model of endocarditis.
Main Methods:
- Utilized isogenic Staphylococcus aureus strains with differential susceptibility or resistance to tPMP-1.
- Established experimental endocarditis in mice by simultaneous challenge with both strains.
- Quantified bacterial densities in vegetations, kidneys, and spleens.
Main Results:
- Significantly higher bacterial densities of the tPMP-resistant (tPMPr) strain were observed in vegetations, kidneys, and spleens compared to the tPMP-susceptible (tPMPs) strain.
- tPMPr strain demonstrated enhanced proliferation within vegetations.
- tPMPr strain showed increased hematogenous dissemination.
Conclusions:
- tPMP-1 effectively limits the proliferation and dissemination of susceptible Staphylococcus aureus strains in experimental endocarditis.
- A tPMP-1 resistant phenotype confers a significant selective advantage to Staphylococcus aureus, promoting enhanced infection progression.
- These findings highlight the importance of tPMP-1 in controlling Staphylococcus aureus endocarditis.