Effects of TB and TB treatment on the pediatric intestinal microbiome

项目摘要/摘要 虽然世界上近四分之一的人口潜伏着感染结核分枝杆菌，但只有 一小部分人会患上活动性结核病。2017年，1000万人患上结核病，其中包括100万儿童。风险 雾化暴露后发展为活动性结核病的因素在很大程度上与年龄和免疫学有关。 能力。然而，需要改进方法来识别患活动性结核病风险最高的人。 人们越来越认识到，微生物群--由生活在地球上的数万亿生物组成 在人体内-在调节宿主新陈代谢和免疫方面起着至关重要的作用。免疫途径 包括共生生物战胜入侵病原体的能力，以及某些植物群 刺激先天免疫反应，继而影响促进粘膜的适应性反应 豁免权。虽然大部分微生物群存在于人体肠道中，但还有其他重要的菌群存在。 在各种其他隔室中，其中最相关的包括肺；正在出现一种 对于这两个隔室之间的串扰，称为肠肺轴。关于结核病，人们知之甚少 关于微生物群可能影响发展为活动性结核病的风险或疾病结局的方式。虽然 众所周知，抗菌药的使用会导致肠道菌群紊乱，对一线的影响 研究了利福平、异烟肼、吡嗪酰胺和乙胺丁醇对结核病原菌群的影响。这个 建议的结核病治疗疗程很长--至少六个月；因此，有人担心这 持续接触抗菌剂的时间可能会对微生物群产生长期影响。 在这项应用中，我们建议评估来自儿科参与者的肠道微生物区系 在对坦桑尼亚农村儿童进行结核病评估的队列研究中招募；我们将使用 在六个月内的三个时间点收集粪便样本，包括任何结核病治疗前的时间点 入会仪式。我们假设，在结核病治疗开始之前，结核病例将表现出对 肠道微生物群可与未患结核病的“对照”儿童区分开来。此外，序列号 对肠道微生物组的评估将展示结核病治疗如何与 微生物学成员资格和功能潜力与不需要或接受的“对照”儿童的比较 结核病治疗。我们将通过以下目标来验证我们的假设：1)评估肠道微生物群 患有结核病的儿童与被排除患有结核病的儿童进行比较，并确定 结核病治疗对肠道微生物群组成、多样性和弹性的纵向影响 在接受结核病治疗的儿童中与对照组进行比较。从粪便标本中提取DNA和超基因组学 测序将在我们在坦桑尼亚的长期合作研究地点进行，生物信息学 分析将由弗吉尼亚大学领导。成功完成这些目标将突出以下方面 肠道微生物群影响结核病的发病机制。

PROJECT SUMMARY/ABSTRACT While nearly one quarter of the world’s population is latently infected with Mycobacterium tuberculosis, only a small fraction develops active TB. In 2017, 10 million people developed TB, including 1 million children. Risk factors for progression to active TB after aerosolized exposure are, in large part, related to age and immunologic competency. However, improved methods are needed to identify people at highest risk of developing active TB. There is a growing appreciation that the microbiome—comprised of the trillions of organisms that live within the human—plays essential roles in the regulation of host metabolism and immunity. Immune pathways include the ability of commensal organisms to outcompete invasive pathogens and the ability of certain flora to stimulate innate immune responses, subsequently influencing adaptive responses that promote mucosal immunity. While the majority of the microbiome is found in the human intestines, additional important flora reside within various other compartments, most relevant of which includes the lungs; there is an emerging appreciation for the cross-talk between these two compartments, termed the gut-lung axis. Regarding TB, little is understood about ways in which the microbiome may impact risk of progression to active TB or disease outcomes. Although it is well known that the use of antimicrobials leads to a disruption in the intestinal flora, the impacts of first-line TB treatment with rifampin, isoniazid, pyrazinamide and ethambutol on the microbiome are understudied. The recommended course of TB treatment is lengthy—at least six months; therefore, there is a concern that this period of continuous antimicrobial exposure can have long-term effects on the microbiome. In this application, we propose to evaluate the intestinal microbiota from pediatric participants who were recruited in a cohort study of children from rural Tanzania undergoing evaluation for TB disease; we will use stool samples collected at three time points over six months, including a timepoint prior to any TB treatment initiation. We hypothesize that prior to TB treatment initiation, “cases” with TB will demonstrate perturbations in the intestinal microbiome that are distinguishable from “control” children without TB. Additionally, serial assessments of the intestinal microbiome will demonstrate how TB treatment is associated with alterations in microbiologic membership and functional potential compared to “control” children who did not need or receive TB treatment. We will test our hypotheses via the following aims: 1) evaluate the intestinal microbiome among children with TB disease compared children who have been ruled out from having TB disease, and 2) determine the longitudinal impacts of TB treatment on the composition, diversity, and resilience of the intestinal microbiome among children on TB treatment compared to controls. DNA extraction from stool samples and metagenomic sequencing will be conducted at our long-term collaborative research sites in Tanzania, and bioinformatic analyses will be led by the University of Virginia. Successful completion of these aims will highlight ways in which the intestinal microbiome affects TB pathogenesis.