Baccani Ilaria, Cuffari Sara, Giuliani Francesco, Rossolini Gian Maria, Pollini Simona
Department of Experimental and Clinical Medicine (DMSC), University of Florence, Largo Brambilla, 3, 50134 Florence, FI, Italy.
Microbiology and Virology Unit, Careggi University Hospital, Largo Brambilla, 3, 50134 Florence, FI, Italy.
Int J Mol Sci. 2025 Aug 5;26(15):7545. doi: 10.3390/ijms26157545.
The emergence and spread of antimicrobial resistance among pathogens are significantly reducing available therapeutic options, highlighting the urgent need for novel and complementary treatment strategies. Antimicrobial photodynamic therapy (aPDT) is a promising alternative approach that can overcome antimicrobial resistance through a multitarget mechanism of action, exerting direct bactericidal and fungicidal effects with minimal risk of resistance development. Although aPDT has shown efficacy against a variety of pathogens, data on its activity against large collections of clinical multidrug-resistant strains are still limited. In this study, we assessed the antimicrobial activity of the photosensitizer RLP068/Cl combined with a red light-emitting LED source at 630 nm (Molteni Farmaceutici, Italy) against a large panel of Gram-negative and Gram-positive bacterial strains harboring relevant resistance traits and species. Our results demonstrated the significant microbicidal activity of RLP068/Cl against all of the tested strains regardless of their resistance phenotype, with particularly prominent activity against Gram-positive bacteria (range of bactericidal concentrations 0.05-0.1 µM), which required significantly lower exposure to photosensitizer compared to and Gram-negative species (range 5-20 µM). Overall, these findings support the potential use of RLP068/Cl-mediated aPDT as an effective therapeutic strategy for the management of localized infections caused by MDR organisms, particularly when conventional therapeutic options are limited.
病原体中抗菌药物耐药性的出现和传播正在显著减少可用的治疗选择，凸显了对新型补充治疗策略的迫切需求。抗菌光动力疗法（aPDT）是一种有前景的替代方法，它可以通过多靶点作用机制克服抗菌药物耐药性，以最小的耐药性发展风险发挥直接的杀菌和杀真菌作用。尽管aPDT已显示出对多种病原体有效，但其针对大量临床多重耐药菌株活性的数据仍然有限。在本研究中，我们评估了光敏剂RLP068/Cl与630nm的红色发光LED光源（意大利Molteni Farmaceutici公司）联合使用时，对一大批具有相关耐药特征的革兰氏阴性和革兰氏阳性细菌菌株及菌种的抗菌活性。我们的结果表明，RLP068/Cl对所有测试菌株均具有显著的杀菌活性，无论其耐药表型如何，对革兰氏阳性细菌的活性尤为突出（杀菌浓度范围为0.05 - 0.1µM），与革兰氏阴性菌（范围为5 - 20µM）相比，所需的光敏剂暴露量显著更低。总体而言，这些发现支持将RLP068/Cl介导的aPDT作为一种有效的治疗策略，用于管理由多重耐药生物体引起得局部感染，特别是在传统治疗选择有限时。
