Defining the role of toxin-antitoxin systems in persistence of Burkholderia pseudomallei

项目摘要/摘要 当务之急是抗击由假鼻疽伯克霍尔德氏菌引起的感染。 对类鼻疽病负有责任。类鼻疽病是世界热带流行地区的一种健康威胁。 在被认为是非地方病的地区，现在被认为是一种紧急疾病。除了引起急性 如果不进行治疗，被认为是致命的感染，细菌可以在宿主体内持续存在，并产生非常 难以治疗潜伏感染。因此，我们的长期目标是开发有效的治疗方法。 类鼻疽和预防潜在或慢性疾病后果。在这个项目中，我们将评估一个 毒素-抗毒素系统的一个子集，已被确定为感知压力的细菌开关之一 并激活一种持久的表型。我们将确定它们与细菌持久性的关联 体外和体内。我们的中心假设是选择性毒素在体内被上调，以响应特定的 条件，以及它们功能的丧失会导致与宿主相关的持久性降低。重要的是要指出 目前对假鼻疽杆菌使用的抗生素产生的持久频率高达50%。因为 研究称，由于假鼻疽杆菌容易产生潜伏感染，目前的治疗方法持续了几个月 毒素-抗毒素系统的研究可以帮助识别新的药物靶点，从而提高抗生素的疗效。我们的 建议的实验方法将侧重于两个具体目标：第一，我们将评估选定的作用 毒素在假鼻疽杆菌感染巨噬细胞期间存活和诱导持续期的作用 这种细胞类型很可能促进潜伏感染；其次，我们将评估B组毒素的贡献。 在寄主相关的活体条件下，假鼻孔菌持续存在的能力。我们的建议意义重大，因为它 有望阐明与持续性有很强关联的特定毒素的作用 表型，这可能导致开发替代治疗方法来防止潜伏期 由疾病预防控制中心B类1级选择性生物制剂和一种未被研究的假鼻疽杆菌引起的感染 新出现的病原体。

Project Summary/Abstract There is an urgent need to combat infections caused by Burkholderia pseudomallei, the bacterial agent responsible for the disease melioidosis. Melioidosis is a health threat in tropical endemic regions of the world and is now recognized as an emergent disease in areas considered non-endemic. In addition to causing acute infections that are considered lethal if left untreated, the bacteria can persist in the host and produce very difficult to treat latent infections. Therefore, our long-term goal is to develop effective treatments against melioidosis and prevent latent or chronic disease outcomes. In this project, we will evaluate the function of a subset of toxin-antitoxin systems that have been identified as one of the bacterial switches that sense stress and activate a persistence phenotype. We will determine their association with bacterial persistence both in vitro and in vivo. Our central hypothesis is that selective toxins are upregulated in vivo in response to specific conditions, and loss of their function results in reduced host-associated persistence. It is important to point out that current antibiotics used against B. pseudomallei generate persister frequencies of up to 50%. Because current treatments last months due to the propensity of B. pseudomallei to generate latent infections, the study of toxin-antitoxin systems can help identify new drug targets and therefore improve antibiotic efficacy. Our proposed experimental approach will focus on two specific aims: first, we will evaluate the role of selected toxins in survival and induction of a persistent stage during B. pseudomallei infection of macrophages because this cell type likely facilitates latent infections; secondly, we will evaluate the contribution of the toxins in B. pseudomallei's ability to persist during host-associated in vivo conditions. Our proposal is significant because it is expected to elucidate the role of the specific toxins that have a strong association with the persistence phenotype, and this might result in the development of alternative therapeutic approaches to prevent latent infections caused by B. pseudomallei, a CDC Category B Tier 1 Select Biothreat Agent and an understudied emerging pathogen.