达托霉素耐药的甲氧西林敏感金黄色葡萄球菌临床分离株的表型和基因型相关性
Phenotypic and genotypic correlates of daptomycin-resistant methicillin-susceptible Staphylococcus aureus clinical isolates.
作者信息
Kang Kyoung-Mi, Mishra Nagendra N, Park Kun Taek, Lee Gi-Yong, Park Yong Ho, Bayer Arnold S, Yang Soo-Jin
机构信息
School of Bioresources and Bioscience, Chung-Ang University, Gyeonggi-do, 17546, Republic of Korea.
Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA.
出版信息
J Microbiol. 2017 Feb;55(2):153-159. doi: 10.1007/s12275-017-6509-1. Epub 2017 Jan 26.
Daptomycin (DAP) has potent activity in vitro and in vivo against both methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains. DAP-resistance (DAP-R) in S. aureus has been mainly observed in MRSA strains, and has been linked to single nucleotide polymorphisms (SNPs) within the mprF gene leading to altered cell membrane (CM) phospholipid (PL) profiles, enhanced positive surface charge, and changes in CM fluidity. The current study was designed to delineate whether these same genotypic and phenotypic perturbations are demonstrated in clinically-derived DAP-R MSSA strains. We used three isogenic DAP-susceptible (DAP-S)/DAP-R strainpairs and compared: (i) presence of mprF SNPs, (ii) temporal expression profiles of the two key determinants (mprF and dltABCD) of net positive surface charge, (iii) increased production of mprF-dependent lysinylated-phosphatidylglycerol (L-PG), (iv) positive surface charge assays, and (v) susceptibility to cationic host defense peptides (HDPs) of neutrophil and platelet origins. Similar to prior data in MRSA, DAP-R (vs DAP-S) MSSA strains exhibited hallmark hot-spot SNPs in mprF, enhanced and dysregulated expression of both mprF and dltA, L-PG overproduction, HDP resistance and enhanced positive surface charge profiles. However, in contrast to most DAP-R MRSA strains, there were no changes in CM fluidity seen. Thus, charge repulsion via mprF-and dlt-mediated enhancement of positive surface charge may be the main mechanism to explain DAP-R in MSSA strains.
达托霉素(DAP)在体外和体内对甲氧西林敏感金黄色葡萄球菌(MSSA)和耐甲氧西林金黄色葡萄球菌(MRSA)菌株均具有强大的活性。金黄色葡萄球菌中的DAP耐药性(DAP-R)主要在MRSA菌株中观察到,并且与mprF基因内的单核苷酸多态性(SNP)有关,这些多态性导致细胞膜(CM)磷脂(PL)谱改变、表面正电荷增强以及CM流动性变化。本研究旨在确定这些相同的基因型和表型扰动是否在临床来源的DAP-R MSSA菌株中出现。我们使用了三对同基因的DAP敏感(DAP-S)/DAP耐药(DAP-R)菌株,并比较了:(i)mprF SNP的存在情况,(ii)净表面正电荷的两个关键决定因素(mprF和dltABCD)的时间表达谱,(iii)mprF依赖性赖氨酰化磷脂酰甘油(L-PG)产量的增加,(iv)表面正电荷测定,以及(v)对中性粒细胞和血小板来源的阳离子宿主防御肽(HDP)的敏感性。与之前MRSA中的数据相似,DAP-R(与DAP-S相比)MSSA菌株在mprF中表现出标志性的热点SNP,mprF和dltA的表达增强且失调,L-PG过量产生,HDP耐药以及表面正电荷谱增强。然而,与大多数DAP-R MRSA菌株不同的是,未观察到CM流动性的变化。因此,通过mprF和dlt介导的表面正电荷增强引起的电荷排斥可能是解释MSSA菌株中DAP-R的主要机制。