HexSDF Is Required for Synthesis of a Novel Glycolipid That Mediates Daptomycin and Bacitracin Resistance in C. difficile.
HexSDF Is Required for Synthesis of a Novel Glycolipid That Mediates Daptomycin and Bacitracin Resistance in C. difficile.
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艰难梭菌是一种革兰氏阳性机会性病原体，每年在美国造成250，000例医院相关感染，12，000例医院相关死亡和10亿美元的医疗费用。最近人们对使用达托霉素类似物surotomycin治疗C.艰难感染。达托霉素与磷脂酰甘油和脂质II相互作用，破坏膜并停止肽聚糖合成。C.艰难梭菌具有不寻常的脂质膜组成，因为它没有磷脂酰丝氨酸或磷脂酰乙醇胺，并且其膜的约50%由糖脂组成，包括独特的C. difficile脂质氨基己糖基-己糖基二酰基甘油（HNHDRG）。我们确定了一个双组分系统（TCS），HexRK，这是C。对达托霉素的艰难耐药性。使用转录组测序（RNA-seq），我们发现HexRK调节hexSDF的表达，hexSDF是一种功能未知的三基因操纵子。基于生物信息学预测，hexS编码单半乳糖基二酰基甘油合酶，hexD编码多糖脱乙酰酶，hexF编码MprF样翻转酶。缺失hexRK导致达托霉素MIC降低4倍，缺失hexSDF导致达托霉素MIC降低8- 16倍。ΔhexSDF突变体对杆菌肽的耐药性也低4倍，但对其他细胞壁活性抗生素没有耐药性。我们的数据表明，在不存在HexSDF的情况下，磷脂膜组成发生改变。野生型C.在艰难梭菌中，独特的糖脂HNHDRG占膜中脂质的约17%。然而，在ΔhexSDF突变体中，HNHDRG完全不存在。虽然尚不清楚HNHDRG如何促成达托霉素耐药性，但杆菌肽耐药性的要求表明其在细胞膜生物发生中具有一般作用。
Clostridioides difficile is a Gram-positive opportunistic pathogen responsible for 250,000 hospital-associated infections, 12,000 hospital-associated deaths, and $1 billion in medical costs in the United States each year. There has been recent interest in using a daptomycin analog, surotomycin, to treat C. difficile infections. Daptomycin interacts with phosphatidylglycerol and lipid II to disrupt the membrane and halt peptidoglycan synthesis. C. difficile has an unusual lipid membrane composition, as it has no phosphatidylserine or phosphatidylethanolamine, and ~50% of its membrane is composed of glycolipids, including the unique C. difficile lipid aminohexosyl-hexosyldiradylglycerol (HNHDRG). We identified a two-component system (TCS), HexRK, that is required for C. difficile resistance to daptomycin. Using transcriptome sequencing (RNA-seq), we found that HexRK regulates expression of hexSDF, a three-gene operon of unknown function. Based on bioinformatic predictions, hexS encodes a monogalactosyldiacylglycerol synthase, hexD encodes a polysaccharide deacetylase, and hexF encodes an MprF-like flippase. Deletion of hexRK leads to a 4-fold decrease in daptomycin MIC, and that deletion of hexSDF leads to an 8- to 16-fold decrease in daptomycin MIC. The ΔhexSDF mutant is also 4-fold less resistant to bacitracin but no other cell wall-active antibiotics. Our data indicate that in the absence of HexSDF, the phospholipid membrane composition is altered. In wild-type (WT) C. difficile, the unique glycolipid HNHDRG makes up ~17% of the lipids in the membrane. However, in a ΔhexSDF mutant, HNHDRG is completely absent. While it is unclear how HNHDRG contributes to daptomycin resistance, the requirement for bacitracin resistance suggests it has a general role in cell membrane biogenesis.
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影响因子：
5.2
作者：
Choudhary KS;Mih N;Monk J;Kavvas E;Yurkovich JT;Sakoulas G;Palsson BO
通讯作者：
Palsson BO
影响因子：
3.1
作者：
Deakin, Laura J.;Clare, Simon;Lawley, Trevor D.
通讯作者：
Lawley, Trevor D.
影响因子：
4.2
作者：
Boix, Vicente;Fedorak, Richard N.;Murata, Yoshihiko
通讯作者：
Murata, Yoshihiko
影响因子：
6.4
作者：
Dembek M;Barquist L;Boinett CJ;Cain AK;Mayho M;Lawley TD;Fairweather NF;Fagan RP
通讯作者：
Fagan RP
影响因子：
6.4
作者：
Ahmed UKB;Shadid TM;Larabee JL;Ballard JD
通讯作者：
Ballard JD