DRUG RESISTANCE AND GENE TRANSFER IN H PYLORI

幽门螺杆菌的耐药性和基因转移

• 批准号: 2004287
• 负责人: DOUGLAS Eugene BERG
• 金额: $ 9.99万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2004287
• 关键词: Helicobacter; bacterial genetics; disease /disorder model; drug resistance; erythromycin; genetic library; genetic recombination; genetic strain; genotype; macrolide antibiotics; metronidazole; polymerase chain reaction; restriction fragment length polymorphism; swine; virulence

DESCRIPTION (Adapted from applicant's abstract): This is a revised version of an application to study the molecular genetics of H. pylori (Hp). Dr. Berg took the critique of the previous version so much to heart that he has prepared what is in essence an entirely new application. Therefore, he has not responded in detail to the previous critique and no more need be said about it. The present application is focussed on emerging antibiotic resistance in Hp and on the possibility of extensive genetic exchange within the species. Dr. Berg notes that Hp shows a remarkable genotypic diversity with respect to fingerprinting markers as well as specific proteins such as those implicated in virulence. The molecular basis for this diversity is, however, unknown, though it has been observed that Hp isolates are frequently transformable, often highly so, and could engage in DNA exchange in vivo. As might have been expected, resistance to clathromycin (Cla) and metronidazole (Met), two widely used drugs, has been on the rise, especially in the third world, where these drugs are used indiscriminately. Neither the mechanisms of resistance nor the responsible genes have been identified to date. Dr. Berg has two specific aims, namely to identify and characterize the genes for Cla and Met resistances and to analyze genetic recombination among Hp strains in vivo. In preliminary studies, he has developed the RAPD and PCR-RFLP methods for genotyping of Hp,and shown that these methods are more sensitive than MLEE, and that plasmid variability does not contribute disproportionately to typing specificity. He also showed that RAPD was useful for pedigree analysis of laboratory K12 strains and that observed variations were often at or near the replication terminus, possibly owing to decay of the replication complex at the terminus in strains stored on stabs. With respect to Hp, Dr. Berg has demonstrated infection with multiple Hp strains and confirmed joint multiple infection in a gnotobioticpiglet model - which appears to be a very good model for Hp infection. Finally, he has constructed an ordered cosmid library of 68 units with 3 gaps, and found the order of genes to be quite different from that in a different strain mapped by PFGE.

描述（改编自申请人摘要）：这是一份修订版 一个应用程序的版本，以研究H的分子遗传学。幽门 （Hp）。 贝格博士对前一版本的批评如此之多， 他说，他准备了一个本质上是全新的 应用程序.因此，他尚未详细回应此前 关于它，不需要再多说了。 是集中在新出现的抗生素耐药性的Hp和 物种内部广泛的基因交换的可能性。 贝格博士 注意到Hp在以下方面显示出显著的基因型多样性： 指纹标记物以及特定蛋白质， 与毒性有关这种多样性的分子基础是， 然而，未知，尽管已经观察到Hp分离物是 经常是可转化的，经常是高度可转化的， 体内交换 正如人们所预料的那样， 克拉霉素（Cla）和甲硝唑（Met）是两种广泛使用的药物， 特别是在第三世界，这些药物 不分青红皂白地使用。无论是抵抗机制还是 到目前为止，已经确定了相关基因。 博士贝格有两个具体的目标，即确定和表征 Cla和Met抗性的基因，并分析遗传 Hp菌株之间的重组。在初步研究中， 他开发了用于基因分型的RAPD和PCR-RFLP方法 结果表明，这些方法比 MLEE，以及 质粒 可变性并不成比例地 to typing类型specificity专一.他还指出，RAPD技术在系谱分析中是有用的 实验室K12菌株的分析，观察到的变异是 通常在复制末端或附近，可能是由于 储存在刺上的菌株末端的复制复合物。与 关于幽门螺杆菌，贝格博士已证明感染多种幽门螺杆菌 菌株和确认的关节多重感染， gnotobioticpiglet模型-这似乎是一个非常好的模型， 感染最后，他构建了一个有序的粘粒库， 68个单位有3个缺口，发现基因的顺序相当 与PFGE图谱上的不同菌株有所不同。