School of Pharmacy, Shanxi Medical University, Taiyuan, 030001, China; Medicinal Basic Research Innovation Center of Chronic Kidney Disease, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, China; Shanxi Provincial Key Laboratory of Drug Synthesis and Novel Pharmaceutical Preparation Technology, Shanxi Medical University, Taiyuan, 030001, China.
Department of Pharmacy, The Affiliated Tianfu Hospital of Southwest Medical University (Meishan Tianfu New Area People's Hospital), Meishan, Sichuan, China.
Microb Pathog. 2024 Dec;197:107068. doi: 10.1016/j.micpath.2024.107068. Epub 2024 Oct 28.
The rise of carbapenem-resistant Klebsiella pneumoniae (CRKP) has led to increased morbidity and mortality in clinical patients, highlighting the urgent need for effective antibacterial agents.
We obtained a synthetic compound, MTEBT-3, using hydrophobic triphenylamine as the skeleton and hydrophilic ammonium salts. We determined the MIC of MTEBT-3 using the macro-broth susceptibility testing method. We isolated a clinical CRKP strain ST3984 and performed synergistic antibiotic sensitivity tests, time-kill assays, and resistance evolution studies. Biofilm formation under sub-MIC conditions was evaluated using crystal violet staining and CLSM. Additionally, biofilm proteins and polysaccharides were quantified. We assessed the bactericidal mechanism of MTEBT-3 by examining the integrity of CRKP bacterial cell membranes and analyzing the transcription of virulence-regulating genes via quantitative real-time PCR.
MTEBT-3 exhibited broad-spectrum antibacterial activity with a low resistance rate, achieving the MIC of 8 μg/mL. The compound displayed additive effects with meropenem and imipenem and synergistic effects with tigecycline. It maintained its efficacy over multiple bacterial generations, with no significant increase in resistance observed. Under sub-MIC conditions, the biomass of biofilms was significantly reduced, and the levels of proteins and polysaccharides within the biofilms were markedly lowered in a concentration-dependent manner. The bactericidal mechanism of MTEBT-3 involved disrupting the integrity of CRKP bacterial cell membranes, leading to increased permeability. Quantitative real-time PCR results showed that MTEBT-3 effectively suppressed the expression of key virulence genes, including fimH, wbbM, rmpA, and rmpA2, which are associated with biofilm formation and bacterial adhesion.
The significant antimicrobial activity of MTEBT-3 against clinically isolated CRKP, along with its synergistic or additive effects with commonly used antibiotics, positions it as a promising candidate for treatment. Its ability to disrupt biofilm formation and reduce virulence factor expression further underscores its potential in managing CRKP infections.
耐碳青霉烯类肺炎克雷伯菌（CRKP）的出现导致临床患者的发病率和死亡率上升，这凸显了急需有效的抗菌药物。
我们使用疏水性三苯胺作为骨架和亲水性季铵盐合成了一种合成化合物 MTEBT-3。我们使用宏肉汤药敏试验方法确定 MTEBT-3 的 MIC。我们分离了一株临床 CRKP 株 ST3984，并进行了协同抗生素药敏试验、时间杀伤试验和耐药进化研究。使用结晶紫染色和 CLSM 评估亚 MIC 条件下的生物膜形成。此外，还定量了生物膜蛋白和多糖。我们通过检查 CRKP 细菌细胞膜的完整性并通过定量实时 PCR 分析毒力调节基因的转录来评估 MTEBT-3 的杀菌机制。
MTEBT-3 表现出广谱抗菌活性，耐药率低，达到 8μg/mL 的 MIC。该化合物与美罗培南和亚胺培南具有相加作用，与替加环素具有协同作用。它在多个细菌代中保持其功效，没有观察到耐药性显著增加。在亚 MIC 条件下，生物膜的生物量明显减少，生物膜内的蛋白质和多糖水平呈浓度依赖性显著降低。MTEBT-3 的杀菌机制涉及破坏 CRKP 细菌细胞膜的完整性，导致通透性增加。定量实时 PCR 结果表明，MTEBT-3 有效抑制了关键毒力基因的表达，包括与生物膜形成和细菌黏附相关的 fimH、wbbM、rmpA 和 rmpA2。
MTEBT-3 对临床分离的 CRKP 具有显著的抗菌活性，并且与常用抗生素具有协同或相加作用，使其成为治疗的有前途的候选药物。它破坏生物膜形成和降低毒力因子表达的能力进一步凸显了其在管理 CRKP 感染方面的潜力。
