Micro-evolution of Arthritogenic Mycoplasma hominis in a Single Patient

 描述（由申请方提供）：多种人支原体在健康和免疫功能低下的宿主中引起慢性和机会性感染。人型支原体是第一个被鉴定的人类相关支原体，与泌尿生殖道定植广泛相关，可导致细菌性阴道病、盆腔炎和发热（产后或流产后）。还报告了生殖道外感染，包括慢性关节炎骨髓炎、新生儿的各种并发症和播散性感染，这些感染在免疫功能低下的宿主中可能是致命的。我们对M.关节炎发生过程中的人类基本上未被探索。此外，在慢性关节炎的情况下， 潜在的遗传变化，允许长期殖民，尽管反复抗菌治疗和宿主免疫系统的挑战。我们的知识基础目前受到限制，缺乏一个明确的遗传系统，这种病原体，没有基因组序列信息的任何关节炎分离株和只有两个基因组数据集可用于任何分离的物种。因此，比较基因组测序提出了（i）纵向系列的12个M。人分离株，其在5年期间内从患有脓毒性关节炎的单个患者中回收;和（ii）一组12个临床分离株，包括另外6个血清型、来自不同大陆的两个尿道炎菌株、两个伤口相关分离株、一个四环素抗性分离株和一个已报道基因转移的临床分离株。两个表面脂蛋白在纵向系列中的表达的分析已经证明了高频率的抗原变异的插入/缺失（indel）突变内的均聚物道和一种新的基因表达机制，其中一个大的，40-kb的基因组重复的结果在并列的表面抗原基因与rRNA基因启动子。尽管这种“自下而上”的方法已经提供了对表面抗原变异的显著洞察，但是该提议的两个具体目标被设计为使用“自上而下”的策略，该策略采用下一代测序来全面描绘突变和基因组重排，这些突变和基因组重排代表了人类关节中5年生态位适应期间的宿主内微进化。由于目前只有两个基因组序列可用于M。人的基因组分析，将这些数据与关节炎菌株和12个额外的临床分离株产生的数据进行比较基因组分析，将完善该物种的核心和泛基因组，潜在地揭示与来自不同疾病病理的分离株差异相关的基因、基因岛或移动的遗传元件。这些数据也应该提供洞察不同血清型之间的抗原变异和获得性四环素耐药的机制和收购。最终，通过完成这些特定目标所产生的数据应该提供一个平台，从该平台可以设计和实施改善免疫或化疗干预的策略。

 DESCRIPTION (provided by applicant): Multiple human mycoplasma species cause chronic and opportunistic infections in both healthy and immunocompromised hosts. Mycoplasma hominis, the first human-associated mycoplasma to be identified, is widely associated with urogenital tract colonization that can lead to bacterial vaginosis, pelvic inflammatory disease and fever (post-partum or post-abortion). Extragenital tract infections including chronic arthritis osteomyelitis, assorted complications in newborn infants and disseminated infections have also been reported, which in immunocompromised hosts are potentially fatal. Our understanding of pathogenicity factors and strategies for host adaptation employed by M. hominis during arthritogenesis are largely unexplored. Furthermore, in cases of chronic arthritis, little is known of the underlying genetic changes that permit long term colonization despite the challenges of repeated antimicrobial therapy and the host immune system. Our knowledge base is currently limited by the lack of a defined genetic system for this pathogen, the absence of genome sequence information for any arthritogenic isolate and only two genomic datasets available for any isolates of the species. Accordingly, comparative genome sequencing is proposed for (i) a longitudinal series of twelve M. hominis isolates that were recovered over a 5-year period from a single patient with septic arthritis and (ii) a panel of twelve clinical isolates including an additional six serotypes, two urethritis strains from different continents, two wound-associated isolates, a tetracycline resistant isolate and a clinical isolate for which gene transfer has been reported. Analysis of the expression of two surface lipoproteins in the longitudinal series has demonstrated high frequency antigenic variation by insertion/deletion (indel) mutation within a homopolymeric tract and a novel mechanism of gene expression whereby a large, 40-kb genome duplication results in juxtaposition of a surface antigen gene with a rRNA gene promoter. Although such "bottom up" approaches have provided significant insight into surface antigen variation, two of the Specific Aims of this proposal are designed to use a "top down" strategy employing next generation sequencing to comprehensively delineate mutations and genomic re- arrangements that represent within-host micro-evolution during the 5-year niche adaptation in a human joint. As only two genome sequences are currently available for M. hominis, the comparative genomic analyses of these data to those generated for the arthritis strains and 12 additional clinical isolates will refine the core and pangenomes for the species, potentially revealing genes, gene islands or mobile genetic elements that are differentially associated with isolates from different disease pathologies. These data should also provide insight antigenic variation between different serotypes and the mechanism and acquisition of acquired tetracycline resistance. Ultimately, the data generated by completion of these Specific Aims should provide a platform from which strategies for improved immune or chemotherapeutic intervention can be devised and implemented.