Szymczak Klaudia, Rychłowski Michał, Zhang Lei, Nakonieczna Joanna
Laboratory of Photobiology and Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdańsk, Poland.
Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdańsk, Poland.
Sci Rep. 2025 Jan 8;15(1):1295. doi: 10.1038/s41598-024-84312-4.
Staphylococcus aureus (S. aureus) can survive inside nonprofessional phagocytes such as keratinocytes, enabling it to evade antibiotics and cause recurrent infections once treatment stops. New antibacterial strategies to eliminate intracellular, multidrug-resistant bacteria are needed. This study used a keratinocyte model infected with methicillin-resistant S. aureus (MRSA) to test light-activated compounds, specifically heme-mimetic gallium (III) porphyrin (GaCHP) and visible light, known as antimicrobial photodynamic inactivation (aPDI), for eliminating intracellular MRSA. GaCHP was found to accumulate more in infected cells, particularly within lysosomal structures where MRSA resides. Flow cytometry and fluorescence microscopy revealed significant colocalization of MRSA and GaCHP. Under aPDI, MRSA showed reduced adhesion to host cells and a 70% reduction in the GFP signal from intracellular bacteria. Additionally, light-activated GaCHP significantly decreased the number of extracellular bacteria, reducing the potential for further infection. This study is the first to analyze aPDI toxicity in real time within an infection model, demonstrating that this method is neither cytotoxic nor phototoxic.
金黄色葡萄球菌（S. aureus）能够在非专职吞噬细胞（如角质形成细胞）内存活，这使其能够逃避抗生素的作用，并在治疗停止后引发反复感染。因此，需要新的抗菌策略来消除细胞内的多重耐药细菌。本研究使用感染耐甲氧西林金黄色葡萄球菌（MRSA）的角质形成细胞模型，测试光激活化合物，特别是血红素模拟物镓（III）卟啉（GaCHP）和可见光，即抗菌光动力灭活（aPDI），用于消除细胞内的MRSA。研究发现，GaCHP在感染细胞中积累更多，特别是在MRSA所在的溶酶体结构内。流式细胞术和荧光显微镜显示MRSA与GaCHP有显著的共定位。在aPDI作用下，MRSA对宿主细胞的粘附减少，细胞内细菌的绿色荧光蛋白信号降低了70%。此外，光激活的GaCHP显著减少了细胞外细菌的数量，降低了进一步感染的可能性。本研究首次在感染模型中实时分析aPDI的毒性，证明该方法既无细胞毒性也无光毒性。
