Bai Enhe, Tan Qingwen, Yi Xiong, Yao Jianghui, Duan Yanwen, Huang Yong
Xiangya International Academy of Translational Medicine, Central South University, Changsha 410013, China.
Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha 410013, China.
Antibiotics (Basel). 2025 Jun 23;14(7):640. doi: 10.3390/antibiotics14070640.
Dithiolopyrrolones (DTPs), such as holomycin and thiolutin, exhibit potent antibacterial activities. DTPs contain a disulfide within a unique bicyclic scaffold, which may chelate metal ions and disrupt metal-dependent cellular processes once the disulfide is reductively transformed to thiols. However, the contribution of the intrinsic redox mechanism of DTPs to their antibacterial activity remains unclear. Herein we used pyrroloformamide (Pyf) A, a DTP with a unique formyl substituent, as a prototype to study the antibacterial potential and mechanism against ESKAPE pathogens, in particular carbapenem-resistant (CRKP). The antibacterial and anti-biofilm activities of Pyf A were mainly assessed against clinical CRKP isolates. Propidium iodide staining, scanning electron microscopy, glutathione (GSH) quantification, and reactive oxygen species (ROS) analysis were utilized to infer its anti-CRKP mechanism. The synergistic antibacterial effects of Pyf A and AgNO were evaluated through checkerboard and time-kill assays, as well as in vivo murine wound and catheter biofilm infection models. Pyf A exhibited broad-spectrum antibacterial activity against ESKAPE pathogens with minimum inhibitory concentrations ranging from 0.25 to 4 μg/mL. It also showed potent anti-biofilm effects against CRKP. Pyf A disrupted the cell membranes of CRKP and markedly depleted intracellular GSH without triggering ROS accumulation. Pyf A and AgNO showed synergistic anti-CRKP activities in vitro and in vivo, by disrupting both GSH- and thioredoxin-mediated redox homeostasis. Pyf A acts as a GSH-depleting agent and, when combined with AgNO, achieves dual-targeted disruption of bacterial thiol redox systems. This dual-targeting strategy enhances antibacterial efficacy of Pyf A and represents a promising therapeutic approach to combat CRKP infections.
二硫代吡咯烷酮（DTPs），如全霉素和硫藤黄素，具有强大的抗菌活性。DTPs在独特的双环支架内含有一个二硫键，一旦二硫键被还原转化为硫醇，该二硫键可能螯合金属离子并破坏金属依赖性细胞过程。然而，DTPs的内在氧化还原机制对其抗菌活性的贡献仍不清楚。在此，我们使用具有独特甲酰基取代基的DTP——吡咯甲酰胺（Pyf）A作为原型，研究其对ESKAPE病原体，特别是耐碳青霉烯类（CRKP）病原体的抗菌潜力和机制。主要针对临床CRKP分离株评估了Pyf A的抗菌和抗生物膜活性。利用碘化丙啶染色、扫描电子显微镜、谷胱甘肽（GSH）定量和活性氧（ROS）分析来推断其抗CRKP机制。通过棋盘法和时间杀菌试验，以及体内小鼠伤口和导管生物膜感染模型，评估了Pyf A和AgNO的协同抗菌作用。Pyf A对ESKAPE病原体表现出广谱抗菌活性，最低抑菌浓度范围为0.25至4μg/mL。它还对CRKP表现出强大的抗生物膜作用。Pyf A破坏了CRKP的细胞膜，并显著消耗细胞内GSH，而不会引发ROS积累。Pyf A和AgNO在体外和体内均表现出协同抗CRKP活性，通过破坏GSH和硫氧还蛋白介导的氧化还原稳态。Pyf A作为一种GSH消耗剂，与AgNO联合使用时，可实现对细菌硫醇氧化还原系统的双靶点破坏。这种双靶点策略增强了Pyf A的抗菌效果，代表了一种对抗CRKP感染的有前景的治疗方法。
