S.AUREUS CELL WALLS AND DRUG RESISTANCE IN MRSA AND VRSA

描述(改编自申请人的摘要)：外观 耐甲氧西林临床分离株中的万古霉素耐药株 (和多重耐药)金黄色葡萄球菌使努力变得特别紧迫 为了更好地了解β-内酰胺和糖肽耐药的机制 在这些病原体中。研究计划将有四个主要重点。(A)少校 新的发展，即沉默的mecA的成功“激活” 坐骨神经葡萄球菌的同源物及其导入金黄色葡萄球菌，将是 随后进行了一系列遗传和生化实验。(B)及 (C)：新数据表明，对两种甲氧西林的耐药机制 和万古霉素涉及一种复杂的应激反应，其中许多基因 决定因素参与其中，这是通过将抗生素添加到 生长介质。细胞壁成分的急剧变化 伴随着抗性的表达将伴随着高分辨率 生化技术。高度同源的人的完整基因组 耐甲氧西林金黄色葡萄球菌(MRSA)Col株目前正在测序中 在基因组研究所(TIGR)。将基因组序列放在 另一方面，该计划是构建一个微阵列系统来探索基因网络 在表达对甲氧西林和万古霉素耐药方面操作。这个 微阵列将用于初步定义全球转录图谱 科尔。然后，该轮廓将作为实验中比较的基础 旨在识别基因表达的变化 抗生素或在影响耐药性的特定突变的影响下。 (D)部分将集中于尝试确定独特的遗传决定因素 Col突变株和临床分离株对万古霉素耐药性的研究 转座子诱变与基因芯片技术的结合。这个 该项目应提供对β-内酰胺和 糖肽抗性，迄今未知的遗传和生化特征 葡萄球菌的细胞壁代谢，它也可能有助于 寻找新的抗菌靶点。

DESCRIPTION (Adapted from the Applicant's Abstract): The appearance of vancomycin-resistant strains among clinical isolates of methicillin-resistant (and multiresistant) Staphylococcus aureus places a special urgency on efforts to better understand the mechanism of beta-lactam and glycopeptide resistance in these pathogens. The Research Program will have four main foci. (A) A major new development, namely, the successful "activation" of the silent mecA homologue of Staphylococcus sciuri and its introduction into S. aureus, will be followed up by a combination of genetic and biochemical experiments. (B) and (C): New data indicate that the mechanisms of resistance to both methicillin and vancomycin involve a complex stress response in which numerous genetic determinants participate and which is induced by addition of the antibiotic to the growth medium. The drastic alteration in cell wall composition that accompanies expression of resistance will be followed by high-resolution biochemical techniques. The complete genome of the highly and homogeneously methicillin-resistant S. aureus (MRSA) strain COL is currently being sequenced at The Institute for Genomic Research (TIGR). With the genome sequence in hand, the plan is to construct a microarray system to explore gene networks operating in the expression of resistance to methicillin and vancomycin. The microarrays will be used to initially define a global transcription profile of COL. This profile will then serve as a basis for comparison in experiments designed to identify changes in gene expression that occur upon the addition of antibiotics or under the influence of specific mutations affecting resistance. Part (D) will concentrate on attempts to identify unique genetic determinants of vancomycin resistance in mutants of COL and in clinical isolates by a combination of transposon mutagenesis and the microarray technology. The project should provide new insights into the mechanisms of beta-lactam and glycopeptide resistance, hitherto unknown genetic and biochemical features of staphylococcal cell wall metabolism, and it may also contribute to the identification of new antibacterial targets.