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Clearance of bacteria from cerebrospinal fluid to blood in experimental meningitis
Abstract:
The occurrence and importance of secondary bacteremia in the pathogenesis of and response to therapy in meningitis is uncertain. Streptococcus pneumoniae type III was injected into the cerebrospinal fluid of the cisterna magna in anesthetized, curarized dogs, and sequential simultaneous samples were obtained from the superior sagittal sinus, cisterna magna, and peripheral blood. The results show that: (i) bacteria are rapidly transported from the cerebrospinal fluid to blood but only after active multiplication within the cerebrospinal fluid, and (ii) entrance into the blood from the cerebrospinal fluid occurs before the height of the febrile response or cerebrospinal fluid pleocytosis.
Insights
Secondary bacteremia in meningitis is uncertain. Bacteria spread from cerebrospinal fluid to blood after multiplication, preceding fever and inflammation.
Area of Science:
- Infectious Diseases
- Neuroscience
- Bacteriology
Background:
- The role of secondary bacteremia in meningitis pathogenesis and treatment response remains unclear.
- Meningitis, an inflammation of the membranes surrounding the brain and spinal cord, can lead to systemic complications.
Purpose of the Study:
- To investigate the timing and dynamics of bacterial dissemination from cerebrospinal fluid (CSF) to the bloodstream during meningitis.
- To understand the relationship between bacterial multiplication in the CSF and the onset of systemic inflammatory responses.
Main Methods:
- Introduction of Streptococcus pneumoniae type III into the cisterna magna CSF of anesthetized dogs.
- Sequential, simultaneous blood and CSF sampling from the cisterna magna and superior sagittal sinus.
- Monitoring bacterial load, fever, and CSF pleocytosis.
Main Results:
- Bacteria rapidly translocate from CSF to peripheral blood following active multiplication within the CSF.
- Bacterial entry into the bloodstream precedes the peak febrile response and CSF pleocytosis.
- Demonstrates a clear pathway for systemic spread during pneumococcal meningitis.
Conclusions:
- Bacterial multiplication in the CSF is a prerequisite for secondary bacteremia in this model of meningitis.
- Systemic dissemination occurs early in the infectious process, before the full development of host inflammatory responses.
- These findings highlight the importance of early bacterial control in the CSF to prevent systemic complications.