Hematogenous dissemination of pathogenic and non-pathogenic Leptospira in a short-term murine model of infection.
Hematogenous dissemination of pathogenic and non-pathogenic Leptospira in a short-term murine model of infection.
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DOI：
10.3389/fcimb.2022.917962
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发表时间：
2022
影响因子：
5.7
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中科院分区：
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钩端螺旋体病是由致病性钩端螺旋体引起的一种新发人畜共患病。由于啮齿动物是钩端螺旋体的自然宿主，啮齿动物的致病模型一直有限，但即使在没有疾病的情况下，啮齿动物模型对于了解水库动物的感染也是有价值的。小鼠感染模型由于遗传易感性提供了优势，因此发展小鼠钩端螺旋体感染模型对于进一步了解这种生物的生物学至关重要。此前，我们实验室建立了伯氏疏螺旋体血源性传播的短期小鼠模型，以研究黏附蛋白在宿主内细菌存活和传播中的作用。在这里，我们将这个模型改编成钩端螺旋体。C3H/HeJ小鼠被麻醉，静脉接种，然后细菌被允许循环长达24小时。小鼠被安乐死，注入生理盐水，并采集组织进行培养和DNA纯化。细菌载量用定量聚合酶链式反应测定。在接种病原体和非病原体后，组织中发现了可复制的细菌负荷，证明了该模型在检测不同钩端螺旋体物种和菌株方面的有效性。致病性问号钩端螺旋体在接种后1小时的血液、肝脏、肾脏和膀胱中的负担明显高于非致病性双弯钩端螺旋体。在自然界中，肾脏的定植对致病性钩端螺旋体的生命周期至关重要。在许多器官中发现了可测量的非致病性双弯杆菌的负荷，并在接种后至少三个小时从血液样本中恢复了活的钩端螺旋体，这与以前认为非致病性钩端螺旋体会迅速清除的看法相反。这种钩端螺旋体血源性传播的短期小鼠模型将允许询问对组织定植和逃避宿主防御具有潜在重要性的毒力因子，并为研究钩端螺旋体感染的决定因素提供了一种新的动物模型。
Leptospirosis is an emerging zoonosis caused by pathogenic Leptospira spp. Because rodents are natural hosts of Leptospira, rodent models of pathogenesis have been limited, but are valuable to understand infection in reservoir animals even in the absence of disease. Mouse models of infection provide advantages due to genetic tractability, so developing murine models of Leptospira infection is crucial for further understanding the biology of this organism. Previously our laboratory developed a short-term murine model of Borrelia burgdorferi hematogenous dissemination to investigate the role of adhesion proteins on bacterial survival and dissemination within a host. Here we adapt this model to Leptospira. C3H/HeJ mice are anesthetized, inoculated intravenously, and then bacteria are allowed to circulate for up to twenty-four hours. Mice are euthanized, perfused with saline, and tissues are harvested for culture and DNA purification. Bacterial burdens are determined by quantitative PCR. Reproducible burdens of bacteria were found in tissues upon inoculation with pathogens and non-pathogens, demonstrating the utility of this model to probe different Leptospira species and strains. Pathogenic L. interrogans has a significantly higher burden in blood, liver, kidney, and bladder at one-hour post-inoculation when compared to non-pathogenic L. biflexa. Colonization of the kidney is essential to the life cycle of pathogenic Leptospira in nature. Measurable burdens of non-pathogenic L. biflexa were found in numerous organs and live leptospires were recovered from blood samples for at least three hours post-inoculation, contrary to the previous belief that non-pathogenic leptospires are rapidly cleared. This short-term murine model of Leptospira hematogenous dissemination will allow for the interrogation of virulence factors potentially important for tissue colonization and evasion of host defenses, and represents a novel animal model for investigating determinants of Leptospira infection.