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Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae
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Streptococcus pneumoniae causes experimental meningitis following intranasal and otitis media infections via a

A Marra1, D Brigham

  • 1Protein Design Labs, Inc., Fremont, California 94555, USA. andrea_marra@groton.pfizer.com

Infection and Immunity
|November 14, 2001
PubMed

Insights

Streptococcus pneumoniae can cause meningitis by directly entering the brain, bypassing the bloodstream. This discovery offers new insights into treating pneumococcal meningitis.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Neuroscience

Background:

  • Streptococcus pneumoniae is a leading cause of bacterial meningitis.
  • The typical route of bacterial meningitis involves bloodstream dissemination.

Purpose of the Study:

  • To investigate alternative pathways for Streptococcus pneumoniae to reach the central nervous system.
  • To determine if Streptococcus pneumoniae can cause meningitis independently of bacteremia.

Main Methods:

  • Two animal models were used: intranasal inoculation in mice and transbullar injection in gerbils.
  • Bacterial presence in blood and brain tissue was assessed.
  • A galU mutant of Streptococcus pneumoniae, with impaired bloodstream dissemination, was utilized.

Main Results:

  • Streptococcus pneumoniae rapidly disseminated to the bloodstream and brain in most infected animals.
  • A subset of animals showed brain infection without detectable bacteremia.
  • The galU mutant successfully infected the brain and cerebrospinal fluid despite limited bloodstream spread.

Conclusions:

  • Streptococcus pneumoniae can cause meningitis by bypassing the bloodstream, a novel dissemination route.
  • This non-bacteremic pathway may explain treatment challenges for pneumococcal meningitis.

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