Infectious Diseases, Novartis Institutes for Biomedical Research, Emeryville, California, USA.
Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, Emeryville, California, USA.
Antimicrob Agents Chemother. 2019 Dec 20;64(1). doi: 10.1128/AAC.01490-19.
Upregulated expression of efflux pumps, target mutations, LpxC protein overexpression, and mutations in were previously shown to mediate single-step resistance to the LpxC inhibitor CHIR-090 in Single-step selection experiments using three recently described LpxC inhibitors (compounds 2, 3, and 4) and mutant characterization showed that these mechanisms affect susceptibility to additional novel LpxC inhibitors. Serial passaging of wild-type and efflux pump-defective strains using the LpxC inhibitor CHIR-090 or compound 1 generated substantial shifts in susceptibility and underscored the interplay of efflux and nonefflux mechanisms. Whole-genome sequencing of CHIR-090 passage mutants identified efflux pump overexpression, mutations, and novel mutations in and in PA4465 as determinants of reduced susceptibility. Two new mutations, encoding A214V and G208S, that reduce susceptibility to certain LpxC inhibitors were identified in these studies, and we show that these and other target mutations differentially affect different LpxC inhibitor scaffolds. Lastly, the combination of target alteration (LpxC) and upregulated expression of LpxC was shown to be tolerated in and could mediate significant decreases in susceptibility.
先前的研究表明，外排泵的表达上调、靶标突变、LpxC 蛋白过表达以及 基因的突变可介导大肠埃希菌对 LpxC 抑制剂 CHIR-090 的单步耐药性。
使用三种最近描述的 LpxC 抑制剂（化合物 2、3 和 4）进行单步选择实验和突变特征分析表明，这些机制会影响对其他新型 LpxC 抑制剂的敏感性。使用 LpxC 抑制剂 CHIR-090 或化合物 1 对 野生型和外排泵缺陷菌株进行连续传代，敏感性发生了显著变化，这突出了外排和非外排机制的相互作用。CHIR-090 传代突变体的全基因组测序确定了外排泵过表达、 基因突变以及 基因和 PA4465 中的新突变是降低敏感性的决定因素。在这些研究中发现了两种新的 突变，分别编码 A214V 和 G208S，这些突变可降低对某些 LpxC 抑制剂的敏感性，我们还证明了这些和其他靶标突变会对不同的 LpxC 抑制剂支架产生不同的影响。最后，靶标改变（LpxC）和 LpxC 表达上调的组合在 中被证明是可耐受的，并且可以介导敏感性显著降低。
