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

• 批准号: 10354624
• 负责人: Muhammad Ammar Zafar
• 金额: $ 23.25万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-01 至 2023-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10354624
• 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; 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; Play; 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

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）是医院获得感染的重要来源。由于KPN获得了多 耐药性，治疗变得更加具有挑战性。另一个问题是隔离的增加 被称为“过度毒性”克雷伯氏菌肺炎或HVKPN的菌株已知在A中引起疾病​​表现 社区环境。这些分离株获得了毒力因素的曲目，使它们能够引起 免疫能力的个体中的疾病。最近，多次致命的医院暴发与多次爆发有关 抗药性HVKPN分离株。流行病学研究表明，HVKPN的胃肠道（GI）定植是 一个主要的水库，可以将其转移到无菌地点并引起疾病表现 殖民者主持人。但是，HVKPN肠道定植并不是先前研究的重点 对于胃肠道（GI）的定植和易位不存在。我们最近开发了一个鼠模型 KPN和HVKPN GI定殖，无需抗生素而实现。我们的可处理模型允许 我们可以更好地了解KPN与宿主具有完整肠道微生物组的动态相互作用。 此外，还观察到了人类HVKPN感染商标的化脓性肝脏的发展 在我们的GI殖民模型中。因此，我们建议HVKPN使用特定的途径来促进其 易位，由其毒力决定因素促进。这些决定因素可以用作新的目标 预防疾病状态的发展。最近，使用我们的动物模型，我们观察到 GI定殖后24小时发生易位。但是，HVKPN采取的确切途径和 易位的专门肠细胞（M细胞）仍有待阐明。因此，在AIM＃1中，我们将进行 体外细胞系分析确定HVKPN采取的途径以促进其易位。其次，我们会的 确定宿主M细胞在使用基因敲除小鼠菌株促进HVKPN易位方面的作用。我们的数据暗示 HVKPN特异性铁分子可毒素（IUC）有助于易位过程。 即使IUC在易位中发挥了作用，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AIM 2中采用体内小说高通量方法，我们将 确定推定的HVKPN因素，以促进其易位。我们研究的结果不仅会提供 了解易位过程，但也确定了推定的易位决定因素，这可能是 减轻HVKPN疾病负担的潜在目标。