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Updated: Aug 22, 2026
Inducing Meningococcal Meningitis Serogroup C in Mice via Intracisternal Delivery
Published on: November 5, 2019
Method for inducing experimental pneumococcal meningitis in outbred mice
Damiana Chiavolini1, Sergio Tripodi, Riccardo Parigi
1Dipartimento di Biologia Molecolare, Laboratorio di Microbiologia Molecolare e Biotecnologia, Policlinico Le Scotte, Università di Siena, Viale Bracci, 53100 Siena, Italy. damianac@bu.edu <damianac@bu.edu>
Background:
Streptococcus pneumoniae is the leading cause of bacterial meningitis. Pneumococcal meningitis is associated with the highest mortality among bacterial meningitis and it may also lead to neurological sequelae despite the use of antibiotic therapy. Experimental animal models of pneumococcal meningitis are important to study the pathogenesis of meningitis, the host immune response induced after infection, and the efficacy of novel drugs and vaccines.
Results:
In the present work, we describe in detail a simple, reproducible and efficient method to induce pneumococcal meningitis in outbred mice by using the intracranial subarachnoidal route of infection. Bacteria were injected into the subarachnoid space through a soft point located 3.5 mm rostral from the bregma. The model was tested with several doses of pneumococci of three capsular serotypes (2, 3 and 4), and mice survival was recorded. Lethal doses killing 50 % of animals infected with type 2, 3 and 4 S. pneumoniae were 3.2 x 10, 2.9 x 10 and 1.9 x 10(2) colony forming units, respectively. Characterisation of the disease caused by the type 4 strain showed that in moribund mice systemic dissemination of pneumococci to blood and spleen occurred. Histological analysis of the brain of animals infected with type 4 S. pneumoniae proved the induction of meningitis closely resembling the disease in humans.
Conclusions:
The proposed method for inducing pneumococcal meningitis in outbred mice is easy-to-perform, fast, cost-effective, and reproducible, irrespective of the serotype of pneumococci used.
Insights
This study presents a simple, reproducible method for inducing pneumococcal meningitis in mice. This model aids research into meningitis pathogenesis, host response, and therapeutic interventions for Streptococcus pneumoniae infections.
Area of Science:
- Infectious Diseases
- Microbiology
- Neurology
Background:
- Streptococcus pneumoniae is the primary cause of bacterial meningitis, characterized by high mortality and potential neurological deficits.
- Existing antibiotic treatments for pneumococcal meningitis have limitations, necessitating further research into pathogenesis and novel therapies.
- Animal models are crucial for understanding meningitis, host immune responses, and evaluating new drugs and vaccines.
Purpose of the Study:
- To develop and detail a straightforward, reproducible method for inducing pneumococcal meningitis in outbred mice.
- To establish a reliable animal model for studying Streptococcus pneumoniae pathogenesis and evaluating potential treatments.
Main Methods:
- Induction of meningitis in outbred mice via intracranial subarachnoid injection of Streptococcus pneumoniae.
- Testing of multiple pneumococcal serotypes (2, 3, and 4) with varying doses to determine lethal concentrations.
- Monitoring of mouse survival rates and characterization of disease progression, including systemic dissemination and histological brain analysis.
Main Results:
- A reproducible method for inducing pneumococcal meningitis in mice using the intracranial subarachnoid route was established.
- Lethal doses (50% mortality) for serotypes 2, 3, and 4 were determined as 3.2 x 10^2, 2.9 x 10^2, and 1.9 x 10^3 CFU, respectively.
- Histological analysis confirmed that the induced meningitis in mice closely mimics human pneumococcal meningitis, with observed systemic dissemination in moribund animals.
Conclusions:
- The described method offers a simple, fast, cost-effective, and reproducible approach to induce pneumococcal meningitis in mice.
- This model is effective regardless of the Streptococcus pneumoniae serotype used, providing a versatile tool for research.
- The model's ability to replicate human meningitis pathology supports its utility in preclinical studies.
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