Molecular Epidemiology, Virulence, and Genomic Characterization of Ureaplasmas

描述（由申请人提供）：解脲支原体属。它们寄生在许多健康人​​身上，但也可能引起侵袭性疾病。它们在某些情况下共生并在其他情况下产生系统性感染的原因尚不清楚。越来越多的证据表明，某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，这个概念的证明并不完整。先前研究发病机制的尝试因分型方法不精确、交叉反应、缺乏商业试剂以及可能同时存在多种血清型的事实而受到阻碍。关于 2 种解脲支原体和个别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、较少歧视性的技术未检测到的毒力因子。我们假设解脲支原体的致病性不同。可以通过对临床分离株和 14 种血清型进行基因型分析来识别遗传差异和毒力因子可能不同的表达来解释。这项研究将检查解脲支原体属。来自患有侵袭性感染的人的数据，并将其与没有这些疾病的人的其他数据进行比较。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共生生物中解脲支原体物种和血清型的出现情况； (2) 完善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，用于确定解脲支原体血清型之间以及致病性与共生性分离株血清型之间的遗传相关性； (3) 比较致病性与共生性分离株的多个带状抗原中串联氨基酸重复的大小和数量，这是评估该特征作为疾病预测因子的方法； (4) 使用全局转座子诱变和对所有 14 个血清型和选定的临床分离株的比较基因组分析来鉴定编码潜在毒力因子 lgA1 蛋白酶和磷脂酶 A1、A2 和 C 活性的基因，以寻找这些基因的可能候选者，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。识别入侵菌株的独特特征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、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.