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Updated: Jun 17, 2026
A Mouse Model to Assess Innate Immune Response to Staphylococcus aureus Infection
Published on: February 28, 2019
Photodynamic therapy for methicillin-resistant Staphylococcus aureus infection in a mouse skin abrasion model
Tianhong Dai1, George P Tegos, Timur Zhiyentayev
1Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
Background And Objective:
Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are now known to be a common and important problem in the Unites States. The objective of this study was to investigate the efficacy of photodynamic therapy (PDT) for the treatment of MRSA infection in skin abrasion wounds using a mouse model.
Study Design/Materials And Methods:
A mouse model of skin abrasion wound infected with MRSA was developed. Bioluminescent strain of MRSA, a derivative of ATCC 33591, was used to allow the real-time monitoring of the extent of infection in mouse wounds. PDT was performed with the combination of a polyethylenimine (PEI)-ce6 photosensitizer (PS) and non-coherent red light. In vivo fluorescence imaging was carried out to evaluate the effect of photobleaching of PS during PDT.
Results:
In vivo fluorescence imaging of conjugate PEI-ce6 applied in mice indicated the photobleaching effect of the PS during PDT. PDT induced on average 2.7 log(10) of inactivation of MRSA as judged by loss of bioluminescence in mouse skin abrasion wounds and accelerated the wound healing on average by 8.6 days in comparison to the untreated infected wounds. Photobleaching of PS in the wound was overcome by adding the PS solution in aliquots.
Conclusion:
PDT may represent an alternative approach for the treatment of MRSA skin infections.
Insights
Photodynamic therapy (PDT) effectively treated Methicillin-resistant Staphylococcus aureus (MRSA) skin infections in mice, reducing bacterial load and accelerating wound healing. This offers a promising alternative for MRSA infection treatment.
Area of Science:
- Microbiology
- Dermatology
- Photomedicine
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are a significant public health concern in the United States.
- Effective treatment options for MRSA skin infections are crucial.
Purpose of the Study:
- To investigate the efficacy of photodynamic therapy (PDT) for treating MRSA skin infections.
- To evaluate PDT in a preclinical mouse model of skin abrasion wounds.
Main Methods:
- A mouse model of MRSA skin abrasion wound infection was established using a bioluminescent MRSA strain for real-time monitoring.
- Photodynamic therapy (PDT) was administered using a polyethylenimine (PEI)-ce6 photosensitizer and red light.
- In vivo fluorescence imaging assessed photosensitizer photobleaching during PDT.
Main Results:
- PDT achieved an average 2.7 log(10) inactivation of MRSA in infected wounds, evidenced by bioluminescence reduction.
- PDT accelerated wound healing by an average of 8.6 days compared to untreated controls.
- The photobleaching effect of the photosensitizer was mitigated by administering the solution in aliquots.
Conclusions:
- Photodynamic therapy (PDT) shows potential as an alternative treatment for MRSA skin infections.
- The study demonstrates the feasibility and effectiveness of PDT in a relevant preclinical model.
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