We have demonstrated that ivacaftor displays synergistic antibacterial activity in combination with polymyxin B against polymyxin-resistant Pseudomonas aeruginosa that commonly colonizes the lungs of people with cystic fibrosis (CF). However, the underlying mechanism(s) remain unclear. In the present study, we employed untargeted metabolomics to investigate the synergistic killing mechanism of polymyxin B in combination with ivacaftor against a polymyxin-susceptible P. aeruginosa FADDI-PA111 (polymyxin B MIC = 2 mg/L) and a polymyxin-resistant CF P. aeruginosa FADDI-PA006 (polymyxin B MIC = 8 mg/L). Metabolites were extracted at 3 h after treatments with polymyxin B alone (2 μg/mL for FADDI-PA111 and 4 μg/mL FADDI-PA006 P. aeruginosa), ivacaftor alone (8 μg/mL), and in combination. Polymyxin B monotherapy induced significant perturbations in the glycerophospholipid and fatty acid metabolism pathways against FADDI-PA111 and to a lesser extent in FADDI-PA006. In both strains, treatment with ivacaftor alone induced more pronounced perturbations in glycerophospholipid and fatty acid metabolism pathways than that with polymyxin B alone. This highlights the unique antimicrobial mode of action of ivacaftor. Pathway analysis revealed that in combination treatment, polymyxin B mediated killing is elevated by ivacaftor, largely due to the inhibition of cell envelope biogenesis via suppression of key membrane lipid metabolites (e.g., sn-glycerol 3-phosphate and sn-glycero-3-phosphoethanolamine) as well as perturbations in peptidoglycan and lipopolysaccharide biosynthesis. Furthermore, significant perturbations in the levels of amino sugars and nucleotide sugars, glycolysis, the tricarboxylic acid cycle, and pyrimidine ribonucleotide biogenesis were observed with the combination treatment. These findings provide novel mechanistic information on the synergistic antibacterial activity of polymyxin–ivacaftor combination.

中文翻译：

---

Ivacaftor升高多粘菌素B介导的囊性纤维化铜绿假单胞菌抗菌活性的代谢组学描述。

我们已经证明，依伐卡托与多粘菌素B结合使用对抵抗多粘菌素的铜绿假单胞菌（Pseudomonas aeruginosa）具有协同增效的抗菌作用，铜绿假单胞菌通常定植在患有囊性纤维化（CF）的人的肺部。但是，基本机制仍不清楚。在本研究中，我们采用非靶向代谢组学研究了多粘菌素B与依伐卡托联用对多粘菌素敏感铜绿假单胞菌FADDI-PA111（多粘菌素B MIC = 2 mg / L）和多粘菌素耐药性CF P的协同杀伤机制。铜绿假单胞菌FADDI-PA006（多粘菌素B MIC = 8 mg / L）。单独用多粘菌素B处理后3小时提取代谢物（对于FADDI-PA111为2μg/ mL，对于FADDI-PA006 P. aeruginosa为4μg/ mL），单独使用依伐卡托（8μg/ mL）和组合使用。多粘菌素B单一疗法在针对FADDI-PA111的甘油磷脂和脂肪酸代谢途径中引起显着扰动，而在FADDI-PA006中则引起较小程度的扰动。在两种菌株中，单独使用依伐卡托治疗均比单独使用多粘菌素B引起更明显的甘油磷脂和脂肪酸代谢途径扰动。这突出了依伐卡托独特的抗菌作用方式。途径分析表明，在联合治疗中，依伐卡托可增加多粘菌素B介导的杀伤作用，这主要是由于通过抑制关键膜脂质代谢产物（例如，Sn -3-磷酸甘油和Sn-甘油-3-磷酸乙醇胺）以及肽聚糖和脂多糖生物合成中的扰动。此外，在联合处理下，观察到氨基糖和核苷酸糖水平的显着扰动，糖酵解，三羧酸循环和嘧啶核糖核苷酸的生物发生。这些发现提供了关于多粘菌素-伊伐卡特组合的协同抗菌活性的新机制信息。