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Updated: Apr 29, 2026
Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
Published on: January 17, 2025
The accessory gene regulator (agr) controls Staphylococcus aureus virulence in a murine intracranial abscesses model
Jian Gong1, Dongzhi Li2, Jun Yan3
1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing Neurosurgical Institute, Beijing, China.
Background:
Intracranial abscesses are associated with high mortality. Staphylococcus aureus is one of the main pathogens that cause intracranial infection. Until now, there is no report to identify the key effectors of S. aureus during the intracranial infection.
Methods:
The murine intracranial abscesses model induced by S. aureus was constructed. The vital sign and survival rate of mice were observed to evaluate the infection. Histological examination was used to diagnose the pathological alterations of mouse tissues. The sensitivity of S. aureus to whole blood was evaluated by whole-blood killing assay.
Results:
In murine intracranial abscesses model, it was shown that the mortality caused by the accessory gene regulator (agr) locus deficient strain was significant decreased compared with its parent strain. Moreover, we found that RNAIII, the effector of agr system, was essential for the intracranial infection caused by S. aureus. In the further investigation, it was shown that restoration the expression of α-toxin in agr deficient strain could partially recover the mortality in the murine intracranial abscesses model.
Conclusion:
Our data suggested that the agr system of S. aureus is an important virulence determinant in the induction and mortality of intracranial abscesses in mice.
Insights
Staphylococcus aureus intracranial infections are deadly. The accessory gene regulator (agr) system, particularly RNAIII and alpha-toxin, drives mortality in mouse models of brain abscess.
Area of Science:
- Microbiology
- Infectious Diseases
- Neuroscience
Background:
- Intracranial abscesses carry a high mortality rate.
- Staphylococcus aureus is a primary cause of intracranial infections.
- Key virulence factors of S. aureus in brain infections remain unidentified.
Purpose of the Study:
- To identify key Staphylococcus aureus virulence factors in intracranial infections.
- To investigate the role of the accessory gene regulator (agr) system in S. aureus brain abscesses.
Main Methods:
- A murine model of S. aureus intracranial abscess was established.
- Survival rates and vital signs were monitored in infected mice.
- Histological analysis and whole-blood killing assays were performed.
Main Results:
- Mice infected with an agr-deficient S. aureus strain showed significantly reduced mortality.
- RNAIII, an effector of the agr system, was found to be essential for intracranial infection.
- Restoring alpha-toxin expression in the agr-deficient strain partially restored mortality.
Conclusions:
- The Staphylococcus aureus agr system is a critical virulence determinant in murine intracranial abscesses.
- The agr system significantly influences the induction and mortality of brain abscesses.
- Targeting the agr system may offer therapeutic strategies for S. aureus brain infections.
