Modulation of EPEC susceptibility and severity by the microbiome

项目摘要(摘要) 在全球，每年有近17亿例肠道胃肠道感染导致腹泻疾病。更多 令人不安的是，由肠道病原体引起的腹泻疾病每天导致2000多名儿童死亡，是 五岁以下儿童死亡的第二大原因。致病性大肠杆菌(EPEC) 是撒哈拉以南非洲腹泻病的常见罪魁祸首，约占所有腹泻的10% 死亡。EPEC感染在感染艾滋病毒的儿童中不成比例地高，并导致更频繁和更长时间的 腹泻发作的发生率比未感染的同龄人要高。尽管艾滋病毒感染导致了免疫缺陷， EPEC是唯一在这一人群中频繁且持续流行的肠道病原体，这表明 这种关系可能涉及的不仅仅是免疫抑制。此外，我们还发现艾滋病毒 接受抗生素复方新诺明(CTX)的未感染儿童也有更高的易感性和严重程度。 EPEC感染。这特别耐人寻味，因为抗生素的使用和艾滋病毒感染都与 肠道微生物多样性的减少，并促使我们假设易感性和临床严重性 在感染艾滋病毒和接受抗生素治疗的儿童中观察到的EPEC感染是微生物群的结果 多样性降低，这促进了EPEC代谢和毒力基因表达的变化。我们会 在两个目标上测试这一点。在目标1中，我们将通过以下方式评估微生物组作为EPEC毒力的潜在调节器 对HIV+和抗生素治疗的儿童进行16S测序，以确认多样性减少并比较 细菌组成，我们将研究EPEC菌株与临床结果之间的关系，我们将 使用用人类粪便重组的无菌小鼠来评估多样性的变化是否影响EPEC 感染。在目标2中，我们将使用微生物转录组学来确定临床分离株中的基因改变。 然后我们将通过在动物模型中评估毒力来确定基因数据是否正确 我们将确定通过粪便微生物区系移植恢复微生物多样性是否有效 治疗选项。

Project Summary (Abstract) Globally, there are nearly 1.7 billion cases of enteric GI infections that cause diarrheal disease every year. More disturbing, is that diarrheal disease caused by enteric pathogens kills over 2,000 children every day and is the second leading cause of death among children under the age of five. Enteropathogenic Escherichia coli (EPEC) is a common culprit of diarrheal disease in Sub-Saharan Africa, accounting for roughly 10% of all diarrheal deaths. EPEC infections are disproportionately high in children with HIV and cause more frequent and prolonged diarrhea episodes than in the uninfected counterparts. Despite the immune deficiency caused by HIV infection, EPEC is the only enteric pathogen that is frequently and consistently prevalent in this population, suggesting that more than just immune suppression may be involved in this relationship. Further, we have found that HIV uninfected children receiving the antibiotic cotrimoxazole (CTX) also have higher susceptibility and severity of EPEC infection. This is especially intriguing as both antibiotic use and HIV-infection have been correlated with a reduction in gut microbial diversity and has prompted us to hypothesize that the susceptibility and clinical severity of EPEC infection observed in HIV-infected and antibiotic-treated children is a consequence of a microbiome reduced in diversity, which promotes changes in the metabolic and virulence gene expression by EPEC. We will test this in two aims. In Aim 1 we will assess the microbiome as a potential modulator of EPEC virulence by performing 16S sequencing on HIV+ and antibiotic-treated children to confirm reduced diversity and to compare bacterial compositions, we will examine the association between EPEC strain and clinical outcomes and we will use germ-free mice reconstituted with human stool to evaluate whether changes in diversity impact EPEC infection. In Aim 2, we will determine genetic alterations in the clinical isolates using microbial transcriptomics and then we will determine whether the genetic data is correct by assessing virulence in an animal model and we will determine whether restoring microbial diversity via a fecal microbiota transplant would be an effective treatment option.