Dipartimento di Medicina Clinica e Sperimentale, Università di Parma, Parma, Italy.
J Pept Sci. 2013 Sep;19(9):554-65. doi: 10.1002/psc.2532. Epub 2013 Jul 26.
Antimicrobial-peptide-based therapies could represent a reliable alternative to overcome antibiotic resistance, as they offer potential advantages such as rapid microbicidal activity and multiple activities against a broad spectrum of bacterial pathogens. Three synthetic antimicrobial peptides (AMPs), AMP72, AMP126, and also AMP2041, designed by using ad hoc screening software developed in house, were synthesized and tested against nine reference strains. The peptides showed a partial β-sheet structure in 10-mM phosphate buffer. Low cytolytic activity towards both human cell lines (epithelial, endothelial, and fibroblast) and sheep erythrocytes was observed for all peptides. The antimicrobial activity was dose dependent with a minimum bactericidal concentration (MBC) ranging from 0.17 to 10.12 μM (0.4-18.5 µg/ml) for Gram-negative and 0.94 to 20.65 μM (1.72-46.5 µg/ml) for Gram-positive bacteria. Interestingly, in high-salt environment, the antibacterial activity was generally maintained for Gram-negative bacteria. All peptides achieved complete bacterial killing in 20 min or less against Gram-negative bacteria. A linear time-dependent membrane permeabilization was observed for the tested peptides at 12.5 µg/ml. In a medium containing Mg²⁺ and Ca²⁺, the peptide combination with EDTA restores the antimicrobial activity particularly for AMP2041. Moreover, in combination with anti-infective agents (quinolones or aminoglycosides) known to bind divalent cation, AMP126 and AMP2041 showed additive activity in comparison with colistin. Our results suggest the following: (i) there is excellent activity against Gram-negative bacteria, (ii) there is low cytolytic activity, (iii) the presence of a chelating agent restores the antimicrobial activity in a medium containing Mg²⁺ and Ca²⁺, and (iv) the MBC value of the combination AMPs-conventional antibiotics was lower than the MBC of single agents alone.
基于抗菌肽的疗法可能代表了克服抗生素耐药性的可靠选择，因为它们具有快速杀菌活性和对广谱细菌病原体的多种活性等潜在优势。三种合成抗菌肽（AMPs），即 AMP72、AMP126 和 AMP2041，是使用内部开发的专用筛选软件设计的，并对 9 株参考菌株进行了测试。这些肽在 10mM 磷酸盐缓冲液中显示出部分 β-折叠结构。所有肽对人细胞系（上皮、内皮和成纤维细胞）和绵羊红细胞均表现出低细胞毒性。抗菌活性呈剂量依赖性，最低杀菌浓度（MBC）范围为 0.17 至 10.12μM（0.4-18.5μg/ml），用于革兰氏阴性菌和 0.94 至 20.65μM（1.72-46.5μg/ml），用于革兰氏阳性菌。有趣的是，在高盐环境中，革兰氏阴性菌的抗菌活性通常得到维持。所有肽在 20 分钟内或更短时间内对革兰氏阴性菌实现完全杀菌。在 12.5μg/ml 时，测试肽观察到线性时间依赖性的膜通透性。在含有 Mg²⁺和 Ca²⁺的培养基中，EDTA 与肽的组合特别恢复了 AMP2041 的抗菌活性。此外，与已知结合二价阳离子的抗感染药物（喹诺酮类或氨基糖苷类）联合使用时，AMP126 和 AMP2041 与粘菌素相比表现出相加作用。我们的结果表明：（i）对革兰氏阴性菌具有极好的活性，（ii）细胞毒性低，（iii）在含有 Mg²⁺和 Ca²⁺的培养基中添加螯合剂可恢复抗菌活性，（iv）组合 AMP-传统抗生素的 MBC 值低于单药的 MBC 值。
