Biology of hypervirulent Klebsiella pneumoniae translocation from the gastrointestinal tract

高毒力肺炎克雷伯菌从胃肠道易位的生物学

基本信息

批准号：
10515338
负责人：
Muhammad Ammar Zafar
金额：
$ 19.38万
依托单位：
WAKE FOREST UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-11-01 至 2024-10-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10515338
关键词：
Adhesions Affect Animal Model Antibiotics Antigens Bacteria Bacterial Translocation Biological Biological Assay Biology Blood Vessels Cell Line Data Development Disease Disease Outbreaks Enterocytes Event Future Gastrointestinal tract structure Goals Hospitals Hour Human ITGB2 gene Immunocompetent In Vitro Individual Infection Intervention Intestinal permeability Intestines Invaded Iron Klebsiella pneumoniae Knockout Mice Knowledge Libraries Life Link Liver Lymphatic Lymphatic System Lymphoid Tissue M cell Modeling Molecular Mouse Strains Multi-Drug Resistance Mus Nosocomial Infections Oral Output Pathogenesis Pathway interactions Patients Phagocytes Phase Prevention Process Public Health Publishing Pyogenic Liver Abscess Role Route Sampling Site Source Spleen Sterility Systemic infection Testing Therapeutic Trademark Variant Vascular System Villus Virulence Virulence Factors aerobactin burden of illness combat community setting design enteric pathogen epidemiologic data epidemiology study fitness gastrointestinal genome-wide gut colonization gut microbiome healthcare-associated infections host colonization host microbiota in vivo insight intestinal epithelium mortality mouse model mutant new therapeutic target novel prevent public health relevance

项目摘要

Description. Klebsiella pneumoniae (Kpn) is a significant source of hospital-acquired infections. As Kpn has acquired multi- drug resistance, it has become even more challenging to treat. Another concern is the increase in isolation of strains termed as "hypervirulent" Klebsiella pneumoniae or hvKpn known to cause disease manifestations in a community setting. These isolates have acquired a repertoire of virulence factors, which allow them to cause disease in immunocompetent individuals. Recently, multiple fatal hospital outbreaks have been linked to multi- drug resistant hvKpn isolates. Epidemiological studies suggest that gastrointestinal (GI) colonization of hvKpn is a major reservoir through which it can translocate to sterile sites and cause disease manifestations in the colonized host. However, hvKpn gut colonization has not been the focus of previous studies as a tractable model for gastrointestinal (GI) colonization and translocation did not exist. We recently developed a murine model of Kpn and hvKpn GI colonization, achieved without the requirement of antibiotics. Our tractable model allows us a better understanding of the dynamic interactions of Kpn with the host with an intact gut microbiome. Moreover, development of pyogenic liver abscess a trademark of hvKpn infections in humans was also observed in our GI model of colonization. Thus, we propose that hvKpn uses specific pathways to promote its translocation, facilitated by its virulence determinants. These determinants can serve as novel targets for the prevention of the development of the disease state. More recently, with our animal model, we observed translocation to occur 24 hours post-GI colonization. However, the exact route(s) taken by hvKpn and the role of specialized enterocytes (M-cells) in translocation remains to be elucidated. Thus, in Aim #1, we will carry out in vitro cell line assays to determine the pathway(s) taken by hvKpn to promote its translocation. Secondly, we will determine the host M-cells' role in promoting hvKpn translocation using knockout mice strains. Our data suggest that hvKpn specific iron acquisition molecule aerobactin (iuc) contributes towards the translocation process. Even though iuc plays a role in translocation, an iuc mutant does not entirely abrogate it, suggesting that other factors are critical for translocation. By taking an in vivo novel high-throughput approach in Aim #2, we will identify putative hvKpn factors that promote its translocation. Results from our studies will not only provide an understanding of the translocation process but also identify putative translocation determinants, which could be potential targets to reduce the hvKpn disease burden.

描述。肺炎克雷伯菌 (Kpn) 是医院获得性感染的重要来源。由于 Kpn 收购了多家耐药性，治疗变得更加困难。另一个担忧是隔离的增加被称为“高毒力”肺炎克雷伯菌或 hvKpn 的菌株，已知会引起疾病表现社区设置。这些分离株获得了一系列毒力因子，使它们能够引起免疫功能健全的个体中的疾病。最近，多起致命的医院疫情爆发与多起事件有关耐药 hvKpn 分离株。流行病学研究表明 hvKpn 的胃肠道 (GI) 定植与一个主要的储存库，它可以通过它转移到无菌部位并在体内引起疾病表现被殖民的宿主。然而，hvKpn 肠道定植作为一种易于处理的模型并不是以前研究的焦点不存在胃肠道（GI）定植和易位。我们最近开发了一个小鼠模型 Kpn 和 hvKpn 胃肠道定植，无需抗生素即可实现。我们的易处理模型允许我们更好地了解 Kpn 与具有完整肠道微生物组的宿主的动态相互作用。此外，还观察到人类 hvKpn 感染的标志性化脓性肝脓肿的发展在我们的 GI 殖民模型中。因此，我们建议 hvKpn 使用特定途径来促进其易位，由其毒力决定因素促进。这些决定因素可以作为新的目标预防疾病状态的发展。最近，通过我们的动物模型，我们观察到易位发生在胃肠道定植后 24 小时。然而，hvKpn 所采取的确切路线以及易位中的特化肠上皮细胞（M 细胞）仍有待阐明。因此，在目标#1中，我们将执行体外细胞系测定以确定 hvKpn 促进其易位的途径。其次，我们将使用敲除小鼠品系确定宿主 M 细胞在促进 hvKpn 易位中的作用。我们的数据表明 hvKpn 特异性铁获取分子 aerobactin (iuc) 有助于易位过程。尽管 iuc 在易位中发挥作用，但 iuc 突变体并不能完全消除它，这表明其他因素对于易位至关重要。通过在目标#2中采用体内新颖的高通量方法，我们将确定促进其易位的推定 hvKpn 因素。我们的研究结果不仅会提供了解易位过程，还确定假定的易位决定因素，这可能是减少 hvKpn 疾病负担的潜在目标。