Contribution of different pneumococcal virulence factors to experimental meningitis in mice

Susanna Ricci, Alice Gerlini, Andrea Pammolli, Damiana Chiavolini, Velia Braione, Sergio A. Tripodi, Bruna Colombari, Elisabetta Blasi, Marco R. Oggioni, Samuele Peppoloni, Gianni Pozzi

Research output: Contribution to journalArticle

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Abstract

Background: Pneumococcal meningitis (PM) is a life-threatening disease with a high case-fatality rate and elevated risk for serious neurological sequelae. In this study, we investigated the contribution of three major virulence factors of Streptococcus pneumoniae, the capsule, pneumococcal surface protein A (PspA) and C (PspC), to the pathogenesis of experimental PM.Methods: Mice were challenged by the intracranial route with the serotype 4 TIGR4 strain (wt) and three isogenic mutants devoid of PspA, PspC, and the capsule. Survival, bacterial counts, and brain histology were carried out. To study the interaction between S. pneumoniae mutants and microglia, phagocytosis and survival experiments were performed using the BV2 mouse microglial cell line.Results: Virulence of the PspC mutant was comparable to that of TIGR4. In contrast, survival of animals challenged with the PspA mutant was significantly increased compared with the wt, and the mutant was also impaired at replicating in the brain and blood of infected mice. Brain histology indicated that all strains, except for the unencapsulated mutant, caused PM. Analysis of inflammation and damage in the brain of mice infected with TIGR4 or its unencapsulated mutant demonstrated that the rough strain was unable to induce inflammation and neuronal injury, even at high challenge doses. Results with BV2 cells showed no differences in phagocytic uptake between wt and mutants. In survival assays, however, the PspA mutant showed significantly reduced survival in microglia compared with the wt.Conclusions: PspA contributed to PM pathogenesis possibly by interacting with microglia at early infection stages, while PspC had limited importance in the disease. The rough mutant did not cause brain inflammation, neuronal damage or mouse death, strengthening the key role of the capsule in PM.

Original languageEnglish (US)
Article number444
JournalBMC Infectious Diseases
Volume13
Issue number1
DOIs
StatePublished - Sep 24 2013

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Pneumococcal Meningitis
Virulence Factors
Meningitis
Microglia
Capsules
Brain
Streptococcus pneumoniae
Protein C
Histology
Inflammation
Bacterial Load
Encephalitis
Phagocytosis
Virulence
pneumococcal surface protein A
Cell Line
Mortality
Wounds and Injuries
Infection

Keywords

  • Capsule
  • Experimental pneumococcal meningitis
  • Microglia
  • PspA
  • PspC

ASJC Scopus subject areas

  • Infectious Diseases

Cite this

Contribution of different pneumococcal virulence factors to experimental meningitis in mice. / Ricci, Susanna; Gerlini, Alice; Pammolli, Andrea; Chiavolini, Damiana; Braione, Velia; Tripodi, Sergio A.; Colombari, Bruna; Blasi, Elisabetta; Oggioni, Marco R.; Peppoloni, Samuele; Pozzi, Gianni.

In: BMC Infectious Diseases, Vol. 13, No. 1, 444, 24.09.2013.

Research output: Contribution to journalArticle

Ricci, S, Gerlini, A, Pammolli, A, Chiavolini, D, Braione, V, Tripodi, SA, Colombari, B, Blasi, E, Oggioni, MR, Peppoloni, S & Pozzi, G 2013, 'Contribution of different pneumococcal virulence factors to experimental meningitis in mice', BMC Infectious Diseases, vol. 13, no. 1, 444. https://doi.org/10.1186/1471-2334-13-444
Ricci, Susanna ; Gerlini, Alice ; Pammolli, Andrea ; Chiavolini, Damiana ; Braione, Velia ; Tripodi, Sergio A. ; Colombari, Bruna ; Blasi, Elisabetta ; Oggioni, Marco R. ; Peppoloni, Samuele ; Pozzi, Gianni. / Contribution of different pneumococcal virulence factors to experimental meningitis in mice. In: BMC Infectious Diseases. 2013 ; Vol. 13, No. 1.
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AU - Tripodi, Sergio A.

AU - Colombari, Bruna

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