Daptomycin is a last-line antibiotic commonly used to treat vancomycin-resistant Enterococci, but resistance evolves rapidly and further restricts already limited treatment options. While genetic determinants associated with clinical daptomycin resistance (DAP^R) have been described, information on factors affecting the speed of DAP^R acquisition is limited. The multiple peptide resistance factor (MprF), a phosphatidylglycerol-modifying enzyme involved in cationic antimicrobial resistance, is linked to DAP^R in pathogens such as methicillin-resistant Staphylococcus aureus. Since Enterococcus faecalis encodes two paralogs of mprF and clinical DAP^R mutations do not map to mprF, we hypothesized that functional redundancy between the paralogs prevents mprF-mediated resistance and masks other evolutionary pathways to DAP^R. Here, we performed in vitro evolution to DAP^R in mprF mutant background. We discovered that the absence of mprF results in slowed DAP^R evolution and is associated with inactivating mutations in ftsH, resulting in the depletion of the chaperone repressor HrcA. We also report that ftsH is essential in the parental, but not in the ΔmprF, strain where FtsH depletion results in growth impairment in the parental strain, a phenotype associated with reduced extracellular acidification and reduced ability for metabolic reduction. This presents FtsH and HrcA as enticing targets for developing anti-resistance strategies.

中文翻译：

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一种重要的蛋白酶 FtsH 影响粪肠球菌中达托霉素耐药性的获得

达托霉素是一种最后一线抗生素，通常用于治疗耐万古霉素肠球菌，但耐药性迅速发展，进一步限制了本已有限的治疗选择。虽然已经描述了与临床达托霉素耐药性 (DAP ^R )相关的遗传决定因素，但影响 DAP ^R获得速度的因素的信息有限。多肽耐药因子 (MprF) 是一种参与阳离子抗菌药物耐药性的磷脂酰甘油修饰酶，与耐甲氧西林金黄色葡萄球菌等病原体中的DAP ^R相关。由于粪肠球菌编码mprF的两个旁系同源物，并且临床 DAP ^R突变未映射到mprF，因此我们假设旁系同源物之间的功能冗余可防止mprF介导的耐药性并掩盖 DAP ^{R 的}其他进化途径。在这里，我们在mprF突变背景下进行了 DAP ^{R 的}体外进化。我们发现mprF的缺失会导致 DAP ^{R进化减慢，并与}ftsH的失活突变相关，从而导致伴侣阻遏蛋白 HrcA 的耗竭。我们还报告说，ftsH在亲本菌株中是必需的，但在 Δ mprF菌株中不是必需的，其中 FtsH 耗尽会导致亲本菌株生长受损，这是一种与细胞外酸化减少和代谢还原能力降低相关的表型。这使得 FtsH 和 HrcA 成为制定抗耐药策略的诱人目标。