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Pneumolysin in pneumococcal adherence and colonization
J B Rubins1, A H Paddock, D Charboneau
1Department of Medicine, Veterans Affairs Medical Center and University of Minnesota School of Medicine, Minneapolis, MN, 55417, USA.
Abstract:
The universal and highly conserved production of pneumolysin, the major pneumococcal cytolysin, among clinical isolates of Streptococcus pneumoniae and the previously reported association of pneumolysin production with increased pneumococcal adherence to respiratory epithelium in organ cultures suggest that this toxin might be important for nasopharyngeal colonization. We confirmed that pneumolysin-deficient mutant pneumococcal strains had decreased adherence to respiratory epithelial cells in vitro compared with their isogeneic wild-type strains. However, neither early nor sustained colonization by type 14 S. pneumoniae in an established murine model was dependent on bacterial production of pneumolysin. We conclude that pneumolysin production is not a major determinant of successful nasopharyngeal colonization by pneumococci.
Insights
Pneumolysin, a toxin from Streptococcus pneumoniae, aids bacterial adherence to cells in lab tests. However, it does not significantly impact nasopharyngeal colonization in mice, suggesting it is not crucial for this process.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Pneumolysin is a universally produced cytolysin in Streptococcus pneumoniae.
- Previous studies suggested a link between pneumolysin and increased bacterial adherence to respiratory epithelium.
- This suggested pneumolysin might play a role in nasopharyngeal colonization.
Purpose of the Study:
- To investigate the role of pneumolysin in Streptococcus pneumoniae adherence to respiratory epithelial cells.
- To determine if pneumolysin production is essential for nasopharyngeal colonization in a murine model.
Main Methods:
- In vitro experiments using pneumolysin-deficient mutant strains and their isogeneic wild-type counterparts to assess adherence to respiratory epithelial cells.
- In vivo colonization studies in a murine model using type 14 S. pneumoniae to evaluate early and sustained nasopharyngeal colonization.
Main Results:
- Pneumolysin-deficient pneumococcal strains showed decreased adherence to respiratory epithelial cells in vitro compared to wild-type strains.
- Bacterial production of pneumolysin was not a determining factor for either early or sustained nasopharyngeal colonization in the murine model.
Conclusions:
- While pneumolysin contributes to pneumococcal adherence in vitro, it is not a major determinant of successful nasopharyngeal colonization.
- The findings indicate that pneumolysin's role in the initial stages of pneumococcal infection, specifically colonization, is limited.