Development of Faux-Biotics to combat the spread of hospital-acquired antibiotic-resistant infections

项目摘要 疾控中心认为抗生素耐药性的升级是最大的公共卫生问题之一 我们的时代。抗生素耐药性是人类和动物健康的主要问题，耐药感染和 抗药性基因可以在动物和与它们互动的人类之间传播。其中一个 最紧迫的威胁是耐碳青霉烯类肠杆菌科细菌(CRE)。抗生素的使用是一个主要的危险因素 用于发展粪便CRE携带者，这既是血液感染的来源，也是传播到其他 易感患者通过与医院工作人员接触。由于缺乏治疗选择，这些 感染可以在高达50%的感染患者中致命。目前恢复殖民的治疗方法 使用粪便微生物区系移植、益生菌或益生菌针对微生物区系进行抗药性。然而，对于 对于必须继续使用抗生素的患者，这些治疗方案不太可能成功。一个健康的人 微生物区系以两种方式提供抗定植能力：通过占据肠道中所有可用的生态位来 直接防止其他微生物群定居，并通过改变肠道环境来 使得它对入侵的细菌不那么受欢迎。后者包括生产短链等物质 脂肪酸，允许微生物区系与宿主细胞相互作用，改善肠道健康和定植 抵抗。该应用程序的目的是设计一种治疗方法，以恢复在 利用微生物群在动态平衡条件下使用的途径的抗生素疗法。我们的 假设是5-ASA，一种激活微生物区系使用的结肠细胞通路的药物，将是 成功恢复对碳青霉烯类耐药肠杆菌科细菌的定植抗性 免疫活性和免疫功能低下的宿主的抗生素治疗。为了检验我们的假设，我们首先 使用抗生素给药和Cre暴露的SPF小鼠模型，无论是否使用5-ASA治疗。 在Cre暴露(预防)之前或在Cre感染之后，小鼠将被置于含有5-ASA的饮食中 (治疗)和定居将通过粪便和盲肠内容物进行监测。然后我们就会感染无菌 用抗生素开始前和抗生素开始后4-7天收集的配对患者粪便样本对小鼠进行重新克隆 抗生素治疗开始了。这些小鼠还将被置于含有5-ASA的饮食中，以证明 可以有效地预防或减少Cre在不同患者体内的定植 各种抗生素疗法。最后，我们将利用环磷酰胺在小鼠中的免疫抑制模型 显示5-ASA介导的肠道CRE CFU减少导致的CRE菌血症减少。 拟议研究的成功完成将提供临床前证据，证明5-ASA是一种临床应用 已获批准的药物，可用于增强对Cre的抵抗力，降低Cre菌血症的风险 通过激活上皮性PPAR-g信号，免疫功能受损的宿主接受抗生素治疗，这是一种范式转变， 将宿主确定为加强殖民抵抗的治疗目标。

Project Summary The CDC considers the escalation of antibiotic resistance to be one of the biggest public health concerns of our time. Antibiotic resistance is a major issue both human and animal health, and resistant infections and resistance genes can be transmitted between animals and the humans who interact with them. One of the most urgent threats is Carbapenem-resistant Enterobacteriaceae (CRE). Antibiotic usage is a major risk factor for the development of fecal CRE carriage, which is both a source of bloodstream infection and spread to other susceptible patients through contact with hospital workers. Due to the lack of treatment options, these infections can be deadly in up to 50% of patients who acquire them. Current therapies to restore colonization resistance target the microbiota using fecal microbiota transplantation, prebiotics, or probiotics. However, for patients who must remain on antibiotics, these treatment options are unlikely to be successful. A healthy microbiota provides colonization resistance in two ways: by occupying all available niches in the intestine to directly prevent other microbiota from colonizing, and through modification of the intestinal environment to make it less welcoming for invading bacteria. The latter includes production of substances such as short-chain fatty acids, which allow the microbiota to interact with host cells and improve intestinal health and colonization resistance. The objective of this application is to devise a treatment to restore colonization resistance during antibiotic therapy that exploit the pathways used by the microbiota under homeostatic conditions. Our hypothesis is that 5-ASA, a drug that activates pathways in colonocytes used by the microbiota, will be successful at restoring colonization resistance against carbapenem resistance Enterobacteriaceae after antibiotic treatment in immunocompetent and immunocompromised hosts. To test our hypothesis, we will first use an SPF mouse model of antibiotic administration and CRE exposure with or without treatment with 5-ASA. Mice will be placed on a 5-ASA-containing diet either prior to CRE exposure (prevention) or after CRE infection (treatment) and colonization will be monitored through feces and cecal contents. We will then infect Germ-free mice recolonized with paired patient fecal samples collected before antibiotics are started and 4-7 days after antibiotic therapy is initiated. These mice will also be placed on a 5-ASA-containing diet to demonstrate that effective prevention or reduction of CRE colonization can be achieved in diverse patient microbiotas with various antibiotic therapies. Finally, we will utilize a cyclophosphamide model of immunosuppression in mice to demonstrate reduced CRE bacteremia as a result of 5-ASA-mediated reduction of intestinal CRE CFU. Successful completion of the proposed research will provide pre-clinical evidence that 5-ASA, a clinically approved drug, can be used to strengthen colonization resistance and lower the risk for CRE bacteremia in an immunocompromised host on antibiotic therapy by activating epithelial PPAR-g signaling, a paradigm shift that establishes the host as a treatment target for strengthening colonization resistance.