Abstract：
The rapid expansion of antibiotic-resistant bacterial diseases is a global burden on public health. It makes sense to repurpose and reposition already-approved medications for use as supplementary agents in synergistic combinations with existing antibiotics. Here, we demonstrate that the anthelmintic drug nitazoxanide (NTZ) synergistically enhances the effectiveness of the lipopeptide antibiotic polymyxin B in inhibiting gram-negative bacteria, including those resistant to polymyxin B. Mechanistic investigations revealed that nitazoxanide inhibited calcium influx and cell membrane depolarization, enhanced the affinity between polymyxin B and the extracellular membrane, and promoted intracellular ATP depletion and an increase in reactive oxygen species (ROS), thus enhancing the penetration and disruption of the Escherichia coli cell membrane by polymyxin B. The transcriptomic analysis revealed that the combination resulted in energy depletion by inhibiting both aerobic and anaerobic respiration patterns in bacterial cells. The increased bactericidal effect of polymyxin B on the E. coli ∆nuoC strain further indicates that NuoC could be a promising target for nitazoxanide. Furthermore, the combination of nitazoxanide and polymyxin B showed promising therapeutic effects in a mouse infection model infected with E. coli. Taken together, these results demonstrate the potential of nitazoxanide as a novel adjuvant to polymyxin B, to overcome antibiotic resistance and improve therapeutic outcomes in refractory infections.IMPORTANCEThe rapid spread of antibiotic-resistant bacteria poses a serious threat to public health. The search for potential compounds that can increase the antibacterial activity of existing antibiotics is a promising strategy for addressing this issue. Here, the synergistic activity of the FDA-approved agent nitazoxanide (NTZ) combined with polymyxin B was investigated in vitro using checkerboard assays and time-kill curves. The synergistic mechanisms of the combination of nitazoxanide and polymyxin B were explored by fluorescent dye, transmission electron microscopy (TEM), and transcriptomic analysis. The synergistic efficacy was evaluated in vivo by the Escherichia coli and mouse sepsis models. These results suggested that nitazoxanide, as a promising antibiotic adjuvant, can effectively enhance polymyxin B activity, providing a potential strategy for treating multidrug-resistant bacteria.
摘要：
抗生素耐药性细菌疾病的迅速扩大是全球公共卫生的负担。在与现有抗生素的协同组合中，重新利用和重新定位已经批准的药物作为补充药物是有意义的。这里,我们证明了驱虫药硝唑尼特（NTZ）协同增强了脂肽抗生素多粘菌素B抑制革兰氏阴性菌的有效性，机制研究表明，硝唑尼特抑制钙内流和细胞膜去极化，增强多粘菌素B与细胞外膜的亲和力，并促进细胞内ATP消耗和活性氧（ROS）的增加，因此，多粘菌素B增强了大肠杆菌细胞膜的渗透和破坏。转录组分析表明，这种组合通过抑制细菌细胞的有氧和无氧呼吸模式而导致能量消耗。多粘菌素B对大肠杆菌ΔnuoC菌株的杀菌作用增强，进一步表明nuoC可能是硝唑尼特的有希望的靶标。此外，硝唑尼特和多粘菌素B的组合在感染大肠杆菌的小鼠感染模型中显示出有希望的治疗效果。一起来看,这些结果证明了硝唑尼特作为多粘菌素B的新型佐剂的潜力，克服抗生素耐药性并改善难治性感染的治疗结果。抗生素耐药性细菌的迅速传播对公众健康构成了严重威胁。寻找可以增加现有抗生素的抗菌活性的潜在化合物是解决该问题的有希望的策略。这里,FDA批准的药物硝唑尼特(NTZ)联合多粘菌素B的协同活性在体外使用棋盘试验和时间-杀伤曲线进行了研究.通过荧光染料探索了硝唑尼特和多粘菌素B组合的协同机制，透射电子显微镜（TEM），和转录组学分析。通过大肠杆菌和小鼠败血症模型在体内评估协同功效。这些结果表明，硝唑尼特，作为一种有前途的抗生素佐剂，能有效增强多粘菌素B活性,提供治疗多重耐药细菌的潜在策略。
