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Updated: Sep 28, 2026
Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
Published on: February 23, 2014
Decreased virulence of a pneumolysin-deficient strain of Streptococcus pneumoniae in murine meningitis
Andreas Wellmer1, Gregor Zysk, Joachim Gerber
1Department of Neurology, University of Göttingen, Göttingen, Germany.
Abstract:
Pneumolysin, neuraminidases A and B, and hyaluronidase are virulence factors of Streptococcus pneumoniae that appear to be involved in the pathogenesis of meningitis. In a murine model of meningitis after intracerebral infection using mutants of S. pneumoniae D39, only mice infected with a pneumolysin-deficient strain were healthier at 32 and 36 h, had lower bacterial titers in blood at 36 h, and survived longer than the D39 parent strain. Cerebellar and spleen bacterial titers, meningeal inflammation, and neuronal damage scores remained uninfluenced by the lack of any of the virulence factors.
Insights
Pneumolysin is a key Streptococcus pneumoniae virulence factor in meningitis. Removing pneumolysin improved mouse survival and health, indicating its critical role in disease pathogenesis.
Area of Science:
- Microbiology
- Infectious Diseases
- Neuroscience
Background:
- Streptococcus pneumoniae possesses several virulence factors, including pneumolysin, neuraminidases A and B, and hyaluronidase.
- These factors are implicated in the pathogenesis of pneumococcal meningitis.
Purpose of the Study:
- To investigate the role of specific Streptococcus pneumoniae virulence factors in a murine meningitis model.
- To determine the contribution of pneumolysin, neuraminidases, and hyaluronidase to meningitis severity and survival.
Main Methods:
- Intracerebral infection of mice with wild-type S. pneumoniae D39 and its isogenic mutants lacking pneumolysin, neuraminidases A and B, or hyaluronidase.
- Assessment of mouse health, bacterial titers in blood and tissues, and histopathological examination of the brain and spleen.
Main Results:
- Mice infected with a pneumolysin-deficient S. pneumoniae strain exhibited improved health and increased survival rates.
- Lower bacterial titers in the blood were observed at 36 hours post-infection in mice lacking pneumolysin.
- Absence of neuraminidases A and B, or hyaluronidase, did not significantly impact mouse health, bacterial loads, or survival.
Conclusions:
- Pneumolysin is a critical virulence factor for Streptococcus pneumoniae in the context of meningitis pathogenesis.
- Targeting pneumolysin may represent a therapeutic strategy to improve outcomes in pneumococcal meningitis.
- Neuraminidases and hyaluronidase appear to play a limited role in the pathogenesis of this S. pneumoniae meningitis model.
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