Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis.
Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis.
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DOI：
10.3390/antibiotics10040404
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发表时间：
2021-04-08
期刊：
影响因子：
--
通讯作者：
Bayer AS
中科院分区：
文献类型：
--
作者：
Yeaman MR;Chan LC;Mishra NN;Bayer AS
口腔炎链球菌（S. mitis-oral）感染在特定人群中越来越普遍，包括中性粒细胞减少癌和心内膜炎患者。在体外和体内实验中，mitis-oral菌株对达托霉素（DAP-R）具有快速、高水平和持久的耐药倾向，尽管其机制尚未完全确定。我们研究了DAP- r对抗阳离子宿主防御肽（hdp）交叉抗性的机制，使用了一个等基因的s.m tis-oral菌株对：(i) DAP-s敏感（DAP- s）亲本351-WT (DAP MIC = 0.5µg/mL)，及其（ii） DAP- r变体351-D10 （DAP MIC > 256µg/mL）。通过流式细胞术定量DAP结合，同时用DAP或比较原型阳离子hdp （hNP-1; LL-37）进行时间（1-4小时）杀伤。多色流式细胞术用于测定与这些分子的抗性或敏感性相关的动态细胞反应。虽然菌株之间的DAP结合总体相似，但351-D10细胞的显著亚群过度积累了DAP（比351-WT高2 - 4倍）。此外，在351-WT中，DAP和hNP-1都诱导了细胞膜（CM）的超极化，与351-D10相比，DAP的杀伤时间显著增加。暴露于DAP、hNP-1或LL-37后，CM通透性、脂质转换或受调节的细胞死亡均未观察到菌株特异性差异。因此，CM的适应性能量学似乎与S. mistis -oral与DAP和选定的HDPs相互作用的结果相耦合。相比之下，CM通透性的改变被认为是DAP和HDPs的主要作用机制，但在这对mitis-oral菌株中，它并没有区分DAP- s和DAP- r的表型。
Streptococcus mitis-oralis (S. mitis-oralis) infections are increasingly prevalent in specific populations, including neutropenic cancer and endocarditis patients. S. mitis-oralis strains have a propensity to evolve rapid, high-level and durable resistance to daptomycin (DAP-R) in vitro and in vivo, although the mechanism(s) involved remain incompletely defined. We examined mechanisms of DAP-R versus cross-resistance to cationic host defense peptides (HDPs), using an isogenic S. mitis-oralis strain-pair: (i) DAP-susceptible (DAP-S) parental 351-WT (DAP MIC = 0.5 µg/mL), and its (ii) DAP-R variant 351-D10 (DAP MIC > 256 µg/mL). DAP binding was quantified by flow cytometry, in-parallel with temporal (1–4 h) killing by either DAP or comparative prototypic cationic HDPs (hNP-1; LL-37). Multicolor flow cytometry was used to determine kinetic cell responses associated with resistance or susceptibility to these molecules. While overall DAP binding was similar between strains, a significant subpopulation of 351-D10 cells hyper-accumulated DAP (>2–4-fold vs. 351-WT). Further, both DAP and hNP-1 induced cell membrane (CM) hyper-polarization in 351-WT, corresponding to significantly greater temporal DAP-killing (vs. 351-D10). No strain-specific differences in CM permeabilization, lipid turnover or regulated cell death were observed post-exposure to DAP, hNP-1 or LL-37. Thus, the adaptive energetics of the CM appear coupled to the outcomes of interactions of S. mitis-oralis with DAP and selected HDPs. In contrast, altered CM permeabilization, proposed as a major mechanism of action of both DAP and HDPs, did not differentiate DAP-S vs. DAP-R phenotypes in this S. mitis-oralis strain-pair.
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