Metagenomics of the circulating blood microbiome and systemic inflammation in preterm infants

项目总结 人类血液循环的无菌性受到了质疑。健康人群循环血微生物菌群的研究 据报道，成人的疾病状态与全身炎症有关，但在 早产儿。我们的初步数据显示，血培养阴性的新生儿的血液 他们被认为没有感染，含有微生物DNA，可以表征为不同的 系统发育类群。这项拟议研究的假设是微生物多样性和 在感染状态下，早产儿循环血微生物组的组成发生改变 如脓毒症，血液微生物群有助于全身炎症。我们将使用一种整体的、多方面的 使用两个特定的目标来检验我们的假设。在具体目标1中，我们将确定微生物 健康早产儿循环血微生物群(细菌、真菌和病毒)的多样性和组成 并与培养阳性和培养阴性败血症的婴儿进行比较。在我们的第二个具体案例中 目的：我们建议确定血液微生物组特征与全身炎症的关系。 和新生儿结局。我们的研究将招募60名早产儿；20名经培养证实患有败血症，20名 新生儿没有败血症，但血培养结果为败血症症状，并呈阴性和 无症状早产儿20例。细菌微生物群将通过元基因组整体猎枪进行评估 以ITS2区和病毒组为靶点对真菌微生物组(真菌生物组)进行测序。大便 皮肤拭子将通过16S rDNA测序进行评估，血清中的细胞因子谱将进行评估。 我们将使用多变量分析将微生物负载、多样性和组成以及细胞因子谱关联起来 临床结果。我们的建议是创新的，因为血液微生物组的存在与 新生儿人群中的炎症和结局尚未报道，将挑战目前的 健康新生儿的无菌血液范例。拟议研究的意义在于，我们将支持 培养阴性败血症的病理生理学，常与过度使用抗生素有关。通过利用 我们最先进的技术、分析工具和德克萨斯医疗中心提供的技术专业知识， 我们准备推进我们对血液微生物群和炎症性损伤的知识，这可能会导致 脆弱早产儿的创新抗炎疗法。

PROJECT SUMMARY The sterility of circulating human blood has been questioned. A circulating blood microbiome in healthy and disease states have been reported in adults associated with systemic inflammation but no such data exists in preterm neonates. Our preliminary data shows that the blood of neonates whose blood cultures were negative and who were considered non-infected, contained microbial DNA that can be characterized into distinct phylogenetic groups. The hypothesis of the proposed research is that the microbial diversity and composition of the circulating blood microbiome in preterm neonates is altered in infective states such as sepsis, and the blood microbiome contributes to systemic inflammation. We will use a holistic, multi- omics approach to test our hypothesis using 2 specific aims. In specific aim 1, we will determine the microbial diversity and composition of the circulating blood microbiome (bacterial, fungal and viral) in healthy preterm neonates and compare it with infants with culture-positive and culture-negative sepsis. In our second specific aim, we propose to determine the association of the blood microbiome signatures with systemic inflammation and neonatal outcomes. Our study will enroll a total of 60 preterm neonates; 20 with culture-proven sepsis, 20 neonates who do not have sepsis but have blood cultures drawn for symptoms of sepsis and were negative and 20 asymptomatic preterm neonates. The bacterial microbiome will be evaluated by metagenomic whole shotgun sequencing, fungal microbiome (mycobiome) by targeting ITS2 region and virome by established methods. Stool and skin swabs will be evaluated by 16S rDNA sequencing and cytokines profiles in the serum will be evaluated. We will use multivariable analyses to correlate microbial load, diversity and composition and cytokine profiles to clinical outcomes. Our proposal is innovative in that the presence of the blood microbiome, it’s association with inflammation and outcomes in the neonatal population has not been reported and will challenge the current paradigm of sterile blood in healthy neonates. The significance of the proposed research is that we will underpin the pathophysiology of ‘culture-negative sepsis’ that is often associated with overuse of antibiotics. By utilizing our state-of-the-science technology, analysis tools and technical expertise available at the Texas Medical Center, we are poised to advance our knowledge on the blood microbiome and inflammatory injury, that may lead to innovative anti-inflammatory therapy in vulnerable preterm infants.