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Updated: May 2, 2026
A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection
Published on: February 28, 2019
Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
Chengwen Zhang1, Chuanfei Xu2, Fumei Luo3
1Medical Research Institute, Southwest University; National Engineering Research Center of Immunological Products, Third Military Medical University.
Abstract:
S. aureus can invade and persist within host cells, including immune cells, which allows it to evade immune detection and clearance. This intracellular persistence contributes to chronic and recurrent infections, complicating treatment and prolonging the disease. Consequently, there is a critical need for an intracellular infection model to better understand, prevent, and treat infections caused by S. aureus. This study indicated that antibiotics effectively eliminated extracellular bacteria but could not eradicate those that had entered the cells. Thus, a stable intracellular infection in vitro was established by RAW264.7 infected with S. aureus and co-culturing them with antibiotics. Subsequently, an intracellular infection model in mice was established by injecting peritoneal macrophages containing the intracellular infection. Vancomycin effectively cleared bacterial loads in mice challenged with planktonic S. aureus; however, it was ineffective against mice infected with equal or lower levels of intracellular bacteria within the peritoneal macrophages. This indicates that the intracellular infection model of S. aureus was successfully established, offering potential insights for the prevention and treatment of intracellular infections.
Insights
Staphylococcus aureus evades antibiotics by hiding inside host cells. Researchers developed an intracellular infection model to study and combat these persistent S. aureus infections.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Staphylococcus aureus invades host cells, including immune cells, leading to chronic infections.
- Intracellular S. aureus evades immune detection and antibiotic treatment.
- A need exists for in vitro and in vivo models of intracellular S. aureus infection.
Purpose of the Study:
- To establish a stable in vitro and in vivo model for intracellular Staphylococcus aureus infection.
- To evaluate the efficacy of vancomycin against intracellular S. aureus.
Main Methods:
- RAW264.7 macrophages were infected with S. aureus and co-cultured with antibiotics to establish an in vitro intracellular infection model.
- Peritoneal macrophages containing intracellular S. aureus were injected into mice to create an in vivo model.
- Vancomycin efficacy was tested against both planktonic and intracellular S. aureus in mice.
Main Results:
- Antibiotics eradicated extracellular S. aureus but not intracellular bacteria.
- The in vitro model successfully established intracellular S. aureus infection within macrophages.
- Vancomycin cleared planktonic S. aureus but was ineffective against intracellular S. aureus in vivo.
Conclusions:
- A stable intracellular infection model for S. aureus was successfully established in vitro and in vivo.
- Intracellular S. aureus is resistant to vancomycin treatment.
- This model provides insights for developing strategies against intracellular S. aureus infections.
