Department of Microbiology, Guru Nanak Dev University, Amritsar, Punjab, India.
Microb Cell Fact. 2020 May 4;19(1):98. doi: 10.1186/s12934-020-01352-x.
An increasing rate of antibiotic resistance among Gram-negative bacterial pathogens has created an urgent need to discover novel therapeutic agents to combat infectious diseases. Use of bacteriocins as therapeutic agents has immense potential due to their high potency and mode of action different from that of conventional antibiotics.
In this study, a novel bacteriocin E20c of molecular weight 6.5 kDa was purified and characterized from the probiotic strain of Enterococcus hirae. E20c had bactericidal activities against several multidrug resistant (MDR) Gram-negative bacterial pathogens. Flow cytometry and scanning electron microscopy studies showed that it killed the Salmonella enterica cells by forming ion-permeable channels in the cell membrane leading to enhanced cell membrane permeability. Further, checkerboard titrations showed that E20c had synergistic interaction with antibiotics such as ampicillin, penicillin, ceftriaxone, and ciprofloxacin against a ciprofloxacin- and penicillin-resistant strain of S. enterica.
Thus, this study shows the broad spectrum antimicrobial activity of novel enterocin E20c against various MDR pathogens. Further, it highlights the importance of bacteriocins in lowering the minimum inhibitory concentrations of conventional antibiotics when used in combination.
革兰氏阴性细菌病原体的抗生素耐药率不断上升，迫切需要发现新的治疗剂来对抗传染病。由于其高效力和不同于传统抗生素的作用模式，细菌素作为治疗剂具有巨大的潜力。
本研究从益生菌屎肠球菌中纯化并鉴定了一种新型分子量为 6.5 kDa 的细菌素 E20c。E20c 对几种多药耐药（MDR）革兰氏阴性细菌病原体具有杀菌活性。流式细胞术和扫描电子显微镜研究表明，它通过在细胞膜中形成离子渗透性通道来杀死肠炎沙门氏菌细胞，导致细胞膜通透性增强。此外，棋盘滴定法显示，E20c 与氨苄西林、青霉素、头孢曲松和环丙沙星等抗生素对耐环丙沙星和青霉素的肠炎沙门氏菌菌株具有协同作用。
因此，本研究表明新型肠球菌素 E20c 对各种 MDR 病原体具有广谱抗菌活性。此外，它强调了当与传统抗生素联合使用时，细菌素在降低最低抑菌浓度方面的重要性。
