Characterizing novel Beta-lactamases from metagenomic samples: insights into the evolution of antimicrobial resistance from the environment towards human-associated pathogens

项目总结 β-内酰胺酶是对β-内酰胺类抗生素最普遍的耐药机制。特别的 令人担忧的是一组被称为碳青霉烯类内酰胺酶的β内酰胺酶，这种酶因其破坏能力而得名 我们最新的β-内酰胺类抗生素，碳青霉烯类。碳青霉烯类耐药性的上升是最近的一次 这一全球趋势导致了泛国家的恐惧。一种有趣的理解方法 碳青霉烯类耐药性及其演变通过非致病性的定量分析 在环境中发现的微生物。这些微生物的分析提供了耐人寻味的 预测抗生素耐药性可能演变的可能性，并为临床医生提供 病原菌出现新的耐药机制的“预警”系统。 先前的研究表明，土壤是许多β-内酰胺酶的极好储存库， 尤其是碳青霉烯酶。该项目的主要部分将是对一系列 从阿拉斯加土壤中分离到的亚基因组起源的β-内酰胺酶，命名为lra(代表对β-内酰胺的抗性 来自阿拉斯加“)。这一元基因组学方法将被扩展并应用于土壤的分析 来自南极洲的样本，以确定不同隔离地区的β-内酰胺酶介导的耐药性。 已鉴定的环境β-内酰胺酶将使用多管齐下的方法进行表征 涉及表型、分子、生化和结构技术。具体地说，结果来自 这一综合分析将使我们能够评估所发现的β-内酰胺酶的进化路线 在当今困扰人类健康的临床病原体中，并评估 可能被这些病原体招募的潜在未被探索的基因。

PROJECT SUMMARY β-Lactamases are the most widespread resistance mechanism to β-lactam antibiotics. Of particular concern are a group of β-lactamases known as carbapenemases, named for their ability to destroy our newest β-lactam antibiotics, the carbapenems. The rise of carbapenem resistance is a recent global trend that has resulted in pan-national fear. An interesting approach to understand carbapenem resistance and how it evolves is through quantitative analysis of non-pathogenic microorganisms found in the environment. Analysis of these microorganisms offers the intriguing possibility of predicting how antibiotic resistance may evolve and provides clinicians with an “early warning” system for the advent of novel resistance mechanisms in pathogenic bacteria. Previous research has shown that the soil is an excellent repository for many β-lactamases, especially carbapenemases. The main part of the project will be the study of a collection of metagenome-origin β-lactamases isolated from Alaskan soil, named LRA (for “β-lactam resistance from Alaska”). This metagenomic approach will be expanded and applied to the analysis of soil samples from Antarctica to identify β-lactamase-mediated resistance in different isolated regions. Identified environmental β-lactamases will be characterized using a multi-pronged approach involving phenotypic, molecular, biochemical and structural techniques. Specifically, results from this comprehensive analysis will allow us to assess the evolutionary routes of β-lactamases found among clinical pathogens that plague human health today, and to evaluate novel niches of potentially unexplored genes that could be recruited by these pathogens.