S. Mitis Species By Housekekeeping Gene Sequencing

通过管家基因测序确定 S. Mitis 物种

• 批准号: 6675248
• 负责人: Steven h FISCHER
• 金额: --
• 依托单位: CLINICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6675248
• 关键词: Streptococcus mitis; bacterial DNA; bacterial genetics; bioterrorism /chemical warfare; gene targeting; genetic library; genetic screening; nucleic acid sequence; ribosomal RNA; species difference

We have submitted an initiative to NIAID for the development of a library of genetic sequences for critical gene targets for bacterial agents of bioterrorism and other closely related organisms. These gene targets include 16S ribosomal RNA genes and essential housekeeping genes (HKG). As a proof of this approach, we have selected viridans group streptococci because they have long been difficult to identify by traditional phenotypic methods. The viridans streptococci are a group of gram-positive bacteria that constitute part of the resident flora in the human oral cavity and gastrointestinal tract. They can occasionally be found as a cause of transient bacteremia, especially following dental procedures. This group of streptococci has become one of the important causative agents of subacute bacterial endocarditis that can result in serious damage of heart valves. Viridans streptococci are composed of at least 22 species, which are currently divided into 5 subgroups: mitis, anginosus, mutans, salivarius, and bovis. Mitis group streptococci are the most common viridans streptococci responsible for diseases in humans. In the past decades, with the emergence of molecular-based methods, re-classification of viridans streptococci has been evolving and is sometimes confusing. One of the reasons for the ambiguity is that conventional biochemical tests used to identify most of the bacteria isolated in the clinical laboratory often do not provide definitive identification at the species level, and may also misidentify members of this group. A new approach for the identification of bacterial pathogens using 16S rDNA gene sequences has been recently introduced. However, this technique has not been helpful in some closely related organisms that have nearly identical sequences in their 16S genes. We have begun exploring a new set of selected HKG that may show a significant number of DNA base differences among members of the viridans streptococci, specifically the mitis group organisms. In comparison to 16S rDNA sequencing, these HKG may result in a better identification system for these organisms.

我们已向NIAID提出一项倡议，要求建立一个生物恐怖主义细菌制剂和其他密切相关生物体关键基因靶点的基因序列库。这些基因靶标包括16S核糖体RNA基因和必需管家基因（HKG）。作为这种方法的证明，我们选择了草绿色组链球菌，因为它们长期以来很难通过传统的表型方法进行鉴定。草绿色链球菌是一组革兰氏阳性细菌，构成人类口腔和胃肠道中常驻植物群的一部分。它们偶尔会被发现是暂时性菌血症的原因，特别是在牙科手术后。这群链球菌已成为亚急性细菌性心内膜炎的重要病原体之一，可导致严重的心脏瓣膜损害。草绿色链球菌由至少22个种组成，目前分为5个亚群：缓症链球菌、咽峡炎链球菌、变异链球菌、唾液链球菌和牛链球菌。缓症组链球菌是最常见的草绿色链球菌负责在人类的疾病。在过去的几十年里，随着分子生物学方法的出现，草绿色链球菌的重新分类一直在发展，有时会引起混淆。模糊的原因之一是，用于识别临床实验室中分离的大多数细菌的常规生化测试通常不能在物种水平上提供明确的识别，并且还可能错误识别该组的成员。利用16S rDNA基因序列鉴定细菌病原体是一种新的方法。然而，这种技术在一些密切相关的生物体中没有帮助，这些生物体在其16S基因中具有几乎相同的序列。我们已经开始探索一组新的选定的HKG，可能会显示显着数量的草绿色链球菌，特别是缓症组生物体的成员之间的DNA碱基差异。与16S rDNA测序相比，这些HKG可能会导致这些生物体的更好的鉴定系统。