Molecular Epidemiology, Virulence, and Genomic Characterization of Ureaplasmas

性状（由申请方提供）：脲原体属它们在许多健康人身上定植，但也可能引起侵入性疾病。它们在某些情况下是寄生虫，而在另一些情况下产生全身感染的原因尚不清楚。越来越多的证据表明，某些脲原体血清型可能比其他血清型具有更大的致病潜力。然而，这个概念的证明是不完整的。先前研究发病机制的尝试受到不精确的分型方法、交叉反应、缺乏商业试剂以及可能同时存在多个血清型的事实的阻碍。关于2种脲原体种属和单个血清型的不同致病性的矛盾结果也表明，可能存在使用较旧的、歧视性较小的技术未检测到的毒力因子。我们推测，不同的致病性脲原体属。可以通过分析临床分离株和14个血清型的基因型来确定遗传差异和可能不同的毒力因子表达来解释。本研究将检查脲原体属。并将其与其他没有这些条件的人进行比较。我们的具体目标是：（1）使用PCR确定来自各种不同条件的临床分离株和寄生生物中的脲原体种和血清型的出现;（2）改进和进一步开发脉冲场凝胶电泳（PFGE）和限制性片段长度多态性，用于确定脲原体血清型之间以及致病性与寄生生物分离株的血清型内的遗传相关性;（3）比较病原性分离物与非病原性分离物的多带抗原中串联氨基酸重复序列的大小和数目，作为评估该特征作为疾病预测因子的手段;（4）鉴定编码潜在毒力因子lgA 1蛋白酶和磷脂酶A1、A2的基因，和C活性，对所有14个血清型和所选临床分离株进行全局转座子诱变和比较基因组分析，以寻找这些基因的可能候选物，然后克隆和表达基因，以确定它们的存在或表达是否与致病结果相关。入侵菌株的独特特征的识别可以指导诊断工具的开发，并指导未来的研究，以提高对影响弱势群体（包括孕妇及其婴儿）的疾病的理解，预防策略和管理。

DESCRIPTION (provided by applicant): Ureaplasma spp. colonize many healthy persons, yet they may also cause invasive diseases. Reasons they are commensals in some instances and produce systemic infections in others are unknown. There is increasing evidence that some Ureaplasma serovars may have a greater pathogenic potential than others. However, proof of this concept is incomplete. Prior attempts to study pathogenesis were hampered by imprecise typing methods, cross-reactions, lack of commercial reagents, and the fact that multiple serovars may be present simultaneously. Contradictory findings regarding differential pathogenicity of the 2 Ureaplasma species and individual serovars also suggests the possibility there may be virulence factors that were not detected using older, less discriminatory techniques. We hypothesize that differential pathogenicity of Ureaplasma spp. may be explained by analyzing clinical isolates and 14 serovars genotypically to identify genetic differences and possibly dissimilar expression of virulence factors. This research will examine Ureaplasma spp. from persons with invasive infections and compare them with others from persons without these conditions. Our Specific Aims are to: (1) Determine occurrence of Ureaplasma species and serovars in clinical isolates from a variety of different conditions and in commensal organisms using PCR; (2) Refine and further develop pulsed field gel electrophoresis (PFGE) and restriction fragment length polymorphism for use in determining genetic relatedness between Ureaplasma serovars and within serovars of pathogenic versus commensal isolates; (3) Compare the size and number of tandem amino acid repeats in multiple banded antigens of pathogenic versus commensal isolates a means to assess this characteristic as a predictor of disease; (4) Identify genes that encode potential virulence factors lgA1 protease and phospholipase A1, A2, and C activities using global transposon mutagenesis and comparative genomic analysis of all 14 serovars and selected clinical isolates to search for likely candidates for these genes, followed by cloning and expressing the genes to determine if their presence or expression correlates with pathogenic outcome. Identification of distinctive features of invasive strains may guide development of diagnostic tools and guide future studies to improve understanding of diseases affecting vulnerable populations including pregnant women and their infants, preventive strategies, and management.