PBP4-mediated β-lactam resistance among clinical strains of Staphylococcus aureus.
PBP4-mediated β-lactam resistance among clinical strains of Staphylococcus aureus.
复制标题
金黄色葡萄球菌临床菌株中 PBP4 介导的 β-内酰胺耐药性。
DOI：
10.1093/jac/dkab201
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Chatterjee,SomS
中科院分区：
文献类型：
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作者：
Satishkumar,Nidhi;Alexander,JAndrewN;Poon,Raymond;Buggeln,Emma;Argudín,MariaA;Strynadka,NatalieCJ;Chatterjee,SomS
背景PBP4是金黄色葡萄球菌中的一种低分子量PBP，不被认为是β-内酰胺耐药的经典介质。我们小组之前用实验室菌株进行了研究。金黄色葡萄球菌证明了 PBP4 通过与 pbp4 启动子和/或基因相关的突变产生 β-内酰胺抗性的能力。 β-内酰胺耐药临床分离株的最新研究。金黄色葡萄球菌已报告了与 pbp4 相关的类似突变。目的确定金黄色葡萄球菌临床菌株中是否报告了 pbp4 相关突变。金黄色葡萄球菌介导β-内酰胺耐药性。方法将来自临床分离株的pbp4启动子和携带突变的基因克隆到异源宿主中。进行报告基因、生长和波西林测定以评估它们在β-内酰胺耐药性中的作用。采用X射线晶体学方法获得WT和突变型PBP4与萘夫西林和头孢西丁的酰基酶中间体结构。结果在含有pbp4启动子突变的5个菌株中，3个菌株表现出PBP4表达增强。 pbp4 中的 R200L 突变导致在 β-内酰胺类萘夫西林和头孢西丁存在下存活率增加。此外，将启动子或基因突变引入WT宿主的基因组中增加了菌株抵抗β-内酰胺作用的能力。所呈现的四个高分辨率 X 射线结构证明了所测试的 β-内酰胺的结合姿势，并为进一步的药物开发提供了线索。结论与 pbp4 启动子和 pbp4 基因相关的突变改变了蛋白质活性，并介导了所研究的临床分离菌株的 β-内酰胺耐药性。
BackgroundPBP4, a low-molecular-weight PBP inStaphylococcus aureus, is not considered to be a classical mediator of β-lactam resistance. Previous studies carried out by our group with laboratory strains ofS. aureusdemonstrated the ability of PBP4 to produce β-lactam resistance through mutations associated with thepbp4promoter and/or gene. Recent studies of β-lactam-resistant clinical isolates ofS. aureushave reported similar mutations associated withpbp4.ObjectivesTo determine ifpbp4-associated mutations reported among clinical strains ofS. aureusmediate β-lactam resistance.MethodsThepbp4promoters and genes bearing mutations from clinical isolates were cloned into a heterologous host. Reporter, growth and Bocillin assays were performed to assess their role in β-lactam resistance. X-ray crystallography was used to obtain acyl-enzyme intermediate structures of the WT and mutant PBP4 with nafcillin and cefoxitin.ResultsOf the five strains that containedpbp4promoter mutations, three strains exhibited enhanced expression of PBP4. The R200L mutation inpbp4resulted in increased survival in the presence of the β-lactams nafcillin and cefoxitin. Further, introduction of either a promoter or a gene mutation into the genome of a WT host increased the ability of the strains to resist the action of β-lactams. The four high-resolution X-ray structures presented demonstrate the binding pose of the β-lactams tested and provide hints for further drug development.ConclusionsMutations associated with thepbp4promoter andpbp4gene altered protein activity and mediated β-lactam resistance among the clinically isolated strains that were studied.