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

描述（改编自申请人的摘要）： 耐甲氧西林临床分离株中万古霉素耐药株 (and多重耐药）金黄色葡萄球菌的工作特别紧迫 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)一个主要 新的发展，即成功“激活”的沉默mecA 松鼠葡萄球菌同源物及其导入S.金黄色，将是 随后进行遗传和生化实验的结合。(B)和 (C)：新的数据表明，对甲氧西林的耐药机制 和万古霉素涉及复杂的应激反应，其中许多遗传 决定因素参与，并通过添加抗生素诱导， 生长介质。细胞壁成分的剧烈变化， 伴随着阻力的表达， 生化技术 高度同质的 耐甲氧西林表皮葡萄金黄色葡萄球菌（MRSA）菌株COL目前正在测序 基因组研究所（TIGR） 基因组序列在 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的抗性中起作用。 的 微阵列将用于初步确定一个全球的转录概况， 然后，该轮廓将作为实验中比较的基础 旨在确定基因表达的变化，发生在添加 抗生素或在影响耐药性的特定突变的影响下。 部分（D）将集中在试图确定独特的遗传决定因素 在COL突变株和临床分离株中， 转座子诱变和微阵列技术相结合。 的 该项目应提供新的见解β-内酰胺的机制， 糖肽抗性，迄今未知的遗传和生化特征， 葡萄球菌细胞壁代谢，它也可能有助于 鉴定新的抗菌靶标。

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.