Identifying host human products responsible for natural transformation of resistance traits in Acinetobacter spp

项目摘要/摘要 近年来，抗药性细菌的出现大量增加。 在临床环境中观察。鲍曼不动杆菌是分布最广的致病菌之一。 引起这些令人震惊的感染。这种细菌以其极端的基因组可塑性为特征， 由水平遗传转移(HGT)过程促进。这些特点是A。 鲍曼尼获得抗药性基因的非凡能力。尽管与外国的 DNA获取到鲍曼不动杆菌的病理生物学，努力阐明机制/S参与 自然转型一直很少见。我们最近证明了人类的存在 胞外宿主液血清白蛋白(HSA)与鲍曼不动杆菌感染增加有关 转型。我们还观察到鲍曼不动杆菌转录产物的表达。 调节因子H-NS对HSA的反应下降，与能力相关的基因表达增加 在h-ns突变株中。这一观察表明，细胞H-NS水平的变化可能在 在自然变化中的核心作用。因此，我们假设HSA与细菌的相互作用 表面成分触发调节信号级联，从而减少H-NS的表达， 从而增强与自然能力相关的基因的表达。为了检验这一假设，我们 将使用受体活性来研究HSA与鲍曼不动杆菌细胞表面蛋白的相互作用- 定向亲和标记(重新标记)技术(目标1)。为了更好地理解转录 反应级联作用于HSA介导的转化效率的提高，我们将 利用互补RNA-seq和DNA序列分析确定H-NS调控的与活性相关的基因 野生型或h-ns突变体的芯片序列分析(目标2)。本申请书中建议的研究将 阐明了在这种具有挑战性的病原体中导致抗生素耐药性的寄主适应过程 全球范围内的相关性日益增强。我们将提供对细菌成分在 HSA信号级联的顶端和H-NS在HSA介导的转录反应中的作用 导致DNA摄取量的增加。未来的研究可以利用这些发现来开发新的 治疗人类严重不动杆菌感染的方法，特别是由新发病毒引起的感染 耐多药菌株。

Project summary/Abstract In recent years, a massive increase in the emergence of antibiotic resistant bacteria has been observed in clinical settings. Acinetobacter baumannii is one of the most widespread pathogens that cause these alarming infections. This bacterium is characterized by its extreme genome plasticity, facilitated by horizontal genetic transfer (HGT) processes. These characteristics are the cause of A. baumannii's remarkable ability to acquire antibiotic-resistance genes. Despite the relevance of foreign DNA acquisition to the pathobiology of A. baumannii, efforts to elucidate the mechanism/s involved in natural transformation have been scarce. We have recently demonstrated that the presence of human serum albumin (HSA) in extracellular host fluids correlates with an increase in A. baumannii natural transformation. We have also observed that the expression of the A. baumannii transcriptional regulator H-NS drops in response to HSA and that competence-associated gene expression increases in the h-ns mutant strains. This observation suggests that changes in cell's H-NS levels may play a central role in natural transformation. Hence, we hypothesize that the interaction of HSA with bacterial surface components triggers a regulatory signaling cascade that decreases H-NS expression, resulting in enhanced expression of genes involved in natural competence. To test this hypothesis, we will examine the interaction of HSA with A. baumannii cell surface proteins using the receptor activity- directed affinity tagging (re-tagging) technique (aim 1). To better understand the transcriptional response cascade responsible for HSA-mediated increase in transformation efficiency, we will determine the H-NS regulated genes associated with competence using complementary RNA-seq and ChIP-seq analyses in wild-type or h-ns mutants (aim 2). The studies proposed in this application will shed light on host adaptation processes leading to antibiotic resistance in this challenging pathogen of increasing relevance worldwide. We will provide new insights into bacterial components acting at the top of the HSA signaling cascade and H-NS's role in HSA-mediated transcriptional responses, leading to an increase in DNA-uptake. Future studies can then use these findings to develop novel approaches to treat severe Acinetobacter human infections, particularly those caused by emerging multidrug-resistant isolates.