Pathogenesis of Haemophilus ducreyi Infections

超出所提供的空间。 杜克雷嗜血杆菌引起软下疳，这是一种生殖器溃疡疾病，有助于艾滋病毒传播。由于缺乏来自自然感染患者的样本，我们开发了一种人类受试者皮肤感染的实验模型，其在临床过程和组织病理学方面都类似于自然疾病。在整个实验感染过程中，H. ducreyi与表皮和真皮上层中的PMN和巨噬细胞共定位，并且与真皮中的胶原蛋白和纤维蛋白共定位。尽管它与吞噬细胞有关，H。在实验感染期间，ducreyi主要保持在细胞外。这些发现与自然感染的相关性尚不清楚。 我们已经在模型中测试了10个同基因突变体/亲本对。许多这些突变体进行了评估，因为在体外研究表明，感兴趣的基因编码的毒力决定因素。然而，只有3个突变体的进展到脓疱形成的能力受损。因此，在体外具有功能的基因通常不会导致体内脓疱的形成。 细菌基因的鉴定是唯一的或差异诱导体内导致了许多基本的观察宿主-病原体相互作用。我们最近放大了//。ducreyi转录物来自实验损伤的活组织检查。随着H. ducreyi基因组序列，我们希望解决关于人类感染期间细菌基因表达的假设，其中细菌暴露于相关组织（人类皮肤）和相关宿主反应。 我们的第一个假设是H. ducreyi在疾病的溃疡阶段继续与PMN、巨噬细胞和胶原蛋白以及纤维蛋白共定位，并且在整个感染过程中主要保持在细胞外。我们的第二个假设是，特定的毒力决定因素差异上调H。ducreyi，并且这些上调基因中的同基因突变体将在模型中减弱。为了测试这些假设，我们的目标包括：本地化的细菌在自然发生的病变;捕获差异上调的细菌转录在体内;在选定的差异上调基因的同基因突变体的建设;在模型中的突变体的评价。 性能现场=

EXCEED THE SPACEPROVIDED. Haemophilus ducreyi causes chancroid, a genital ulcer disease that facilitates HIV transmission. Lacking specimens from naturally infected patients, we developed an experimental model of infection of the skin in human subjects, which resembles natural disease in both its clinical course and histopathology. Throughout the course of experimental infection, the H. ducreyi colocalizes with PMNs and macrophages in the epidermis and upper dermis, and with collagen and fibrin in the dermis. Despite its association with phagocytic cells, H. ducreyi remains predominantly extracellular during experimental infection. The relevance of these findings to natural infection is unknown. We have tested 10 isogenic mutant/parent pairs in the model. Many of these mutants were evaluated because in vitro studies suggested that the gene of interest encoded a virulence determinant. However, only 3 of the mutants were impaired in their ability to progress to pustule formation. Thus, genes that have functions in vitro frequently do not contribute to pustule formation in vivo. Identification of bacterial genes that are exclusively or differentially induced in vivo has led to many fundamental observations about host-pathogen interactions. We recently amplified //. ducreyi transcripts from biopsies of experimental lesions. With the completion of the H. ducreyi genome sequence, we wish to address hypotheses about expression of bacterial genes during human infection, where the bacteria are exposed to a relevant tissue (human skin) and a relevant host response. Our first hypothesis is that H. ducreyi continues to colocalize with PMNs, macrophages and collagen and fibrin during the ulcerative stage of disease and remains primarily extracellular throughout infection. Our second hypothesis is that specific virulence determinants are differentially upregulated by H. ducreyi during infection, and that isogenic mutants in these upregulated genes will be attenuated in the model. To test these hypotheses our aims include: localization of the bacteria in naturally occurring lesions; capture of bacterial transcripts differentially upregulated in vivo; construction of isogenic mutants in selected differentially upregulated genes; evaluation of the mutants in the model. PERFORMANCE SITE ========================================Section End===========================================