Molecular Epidemiology, Virulence, and Genomic Characterization of Ureaplasmas

描述(申请人提供)：解脲支原体。殖民了许多健康的人，但他们也可能导致侵袭性疾病。它们在某些情况下是共性的，而在其他情况下会产生系统性感染的原因尚不清楚。越来越多的证据表明，一些解脲支原体血清型可能比其他血清型具有更大的致病潜力。然而，对这一概念的证明是不完整的。以前研究发病机制的尝试受到不精确的分型方法、交叉反应、缺乏商业试剂以及多个血清可能同时存在的事实的阻碍。关于两个解脲支原体物种和单个血清型的不同致病性的相互矛盾的发现也表明，可能存在使用较旧的、较少歧视的技术没有检测到的毒力因子。我们推测解脲支原体具有不同的致病性。可以通过分析临床分离株和14个血清型来确定遗传差异和可能不同的毒力因子表达来解释。本研究将检测解脲支原体。来自侵袭性感染的人，并将他们与来自没有这些情况的人的其他人进行比较。我们的具体目标是：(1)利用聚合酶链式反应(PCR)确定不同条件下临床分离株和共生生物中解脲支原体种类和血清型的出现；(2)改进和进一步发展脉冲场凝胶电泳(PFGE)和限制性片段长度多态性，用于确定解脲支原体血清型之间和致病与共生分离株之间的遗传亲缘关系；(3)比较致病分离株和共生分离株多条带抗原中串联氨基酸重复序列的大小和数量，作为评估这一特征作为疾病预测因子的手段；(4)通过全球转座子突变和对所有14个血清型和选定的临床分离株的比较基因组分析，确定编码潜在毒力因子lgA1蛋白水解酶和磷脂酶A1、A2和C活性的基因，以寻找这些基因的可能候选基因，然后克隆和表达这些基因，以确定它们的存在或表达是否与致病结果相关。确定侵袭性菌株的独特特征可能会指导诊断工具的开发，并指导未来的研究，以提高对影响包括孕妇及其婴儿在内的脆弱人群的疾病、预防策略和管理的了解。

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.