Identification and characterization of the type II secretion system in carbapenemase-producing Klebsiella pneumoniae ST258

产碳青霉烯酶肺炎克雷伯菌 ST258 的 II 型分泌系统的鉴定和表征

• 批准号: RGPIN-2021-03066
• 负责人: Thomassin, JennyLee
• 金额: $ 2.19万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744339
• 关键词: Identification; characterization; type; II; secretion

My research program is aimed at understanding how bacteria interact with and shape their local environment. Classic Klebsiella pneumoniae strains form part of our normal flora, but can cause life-threatening infections when our immune system is weakened. These infections are becoming more difficult to treat in Canada and abroad because K. pneumoniae have acquired genes that make them resistant to most, and occasionally, all antibiotics. In the context of the ongoing Covid-19 pandemic, use of antibiotics to treat patients combined with increased hospitalisation rates will increase the risk of hospital-acquired infections and spread of multi-drug resistant (MDR) bacteria like K. pneumoniae. The global spread of specific contemporary MDR K. pneumoniae strains, suggests that in addition to drug resistance they have features that contribute to their success. Identifying and characterizing these features has broad implications for how we approach microbiological control and treatment of MDR K. pneumoniae. Studying the biology of these contemporary K. pneumoniae strains is technically challenging because commonly available molecular biology tools that rely on antibiotics cannot be used or are limited due to antimicrobial resistance. The long-term goal of my research program is to characterise mechanisms used by contemporary K. pneumoniae strains to interact with and shape their local environment. Type II secretion systems are used by many Gram-negative bacteria to transport folded proteins in their active form into the environment. These transported proteins allow bacteria to interact with their surrounding environment to promote bacterial pathogenesis and/or environmental survival. The genes encoding the type II secretion system are widespread among Klebsiella. Yet, no comprehensive studies have been performed in K. pneumoniae and the only known transported protein is a starch debranching enzyme used for nutrient acquisition called pullulanase. We hypothesize that the type II secretion system from K. pneumoniae transports more than one protein and that these proteins allow K. pneumoniae to shape its local environment. My short-term objectives are to develop the tools needed to define how K. pneumoniae uses its type II secretion system to interact with its local environment. Specifically, we will apply molecular genetics techniques and functional assays to (1) generate a contemporary model strain of K. pneumoniae compatible with existing molecular biology tools. (2) Define the individual contribution of each component of the K. pneumoniae type II secretion machinery to protein secretion and (3) identify novel secreted proteins. We will generate a model strain that will simplify the study of MDR K. pneumoniae and perform the first systemic analysis of its type II secretion system. Altogether this work will provide insight into how MDR K. pneumoniae interacts with its local environment, which has broad implications for its microbiological control.

我的研究项目旨在了解细菌如何与当地环境相互作用并塑造它们。经典的肺炎克雷伯氏菌菌株构成了我们正常植物群的一部分，但当我们的免疫系统减弱时，会导致危及生命的感染。这些感染在加拿大和国外越来越难以治疗，因为K。肺炎杆菌获得了使它们对大多数抗生素，偶尔是所有抗生素产生耐药性的基因。在2019冠状病毒病（COVID-19）大流行持续的背景下，使用抗生素治疗患者加上住院率增加将增加医院获得性感染和多重耐药（MDR）细菌（如克雷伯氏菌）传播的风险。肺炎。特定当代MDR K的全球传播。pneumoniae菌株，表明除了耐药性外，它们还具有有助于其成功的特征。识别和表征这些特征对我们如何处理MDR K的微生物控制和治疗具有广泛的意义。肺炎。研究这些当代K.肺炎菌株在技术上具有挑战性，因为依赖于抗生素的常用分子生物学工具不能使用或由于抗微生物剂抗性而受到限制。我的研究计划的长期目标是研究当代K。pneumoniae菌株与其局部环境相互作用并塑造其局部环境。II型分泌系统被许多革兰氏阴性细菌用于将折叠蛋白以其活性形式运输到环境中。这些转运蛋白允许细菌与其周围环境相互作用，以促进细菌致病和/或环境存活。编码II型分泌系统的基因在克雷伯氏菌中广泛存在。然而，尚未对K. pneumoniae的蛋白质，并且唯一已知的转运蛋白质是用于营养获取的淀粉脱支酶，称为支链淀粉酶。我们推测K. pneumoniae转运一种以上的蛋白质，这些蛋白质允许K. pneumoniae肺炎to shape形its local本地environment环境.我的短期目标是开发定义K如何所需的工具。肺炎使用其II型分泌系统与其局部环境相互作用。具体而言，我们将应用分子遗传学技术和功能测定（1）产生当代模式菌株的K。pneumoniae与现有的分子生物学工具兼容。(2)定义K的每个分量的单独贡献。肺炎杆菌II型分泌机制对蛋白质分泌的影响和（3）鉴定新的分泌蛋白。我们将产生一个模型菌株，这将简化MDR K的研究。pneumoniae，并对其II型分泌系统进行首次系统分析。总之，这项工作将提供洞察如何MDR K。pneumoniae与其局部环境相互作用，这对其微生物控制具有广泛意义。