Biofilm Formation by Listeria monocytogenes

描述（由申请人提供）：项目摘要：本申请详细介绍了一个为期五年的研究职业发展计划，旨在探索生物膜形成的食源性病原体单核细胞增生李斯特菌的指导下博士罗伯托·科尔特，教授在微生物学和分子遗传学系在哈佛医学院。Kolter博士是微生物生物膜开发领域的领导者，在指导他的学员担任独立调查员方面有着出色的记录。我的长期目标是成为一名独立的临床研究员。为此，我接受了儿科传染病和生物学方面的培训。这个建议的目的是准备我是一个独立的研究人员研究生物膜形成的L。单核细胞增多症这个研究领域与我以前的研究非常不同，我的计划包括细菌代谢和生物信息学的课程。革兰氏阳性菌L.单核细胞增多症是一种食源性病原体，其在胎儿、新生儿和免疫功能低下的人中引起严重甚至致命的感染。L.以生物膜形式存在于食品制备表面上的单核细胞增多症是导致霍乱爆发的污染源。生物膜是微生物细胞高度组织化的、基质封闭的集合体。与医学和食品工业特别相关的是，生物膜细菌对洗涤剂、杀生物剂和抗生素的抵抗力比单个的自由生活的细菌更强。这使得生物膜涂覆表面的去污特别困难。虽然对李斯特菌如何形成生物膜知之甚少，但李斯特菌的发病机制已得到充分研究。因此，有许多遗传和基因组工具可用。本文提出的实验旨在确定：（1）什么L。单核细胞增生基因是使用转座子和靶向诱变形成生物膜所必需的，以及（2）对于L.单核细胞增多症使用DNA微阵列技术。从这些实验中获得的见解应该导致新的方法来净化生物膜涂层表面，并更好地了解生物膜一般。相关性：通过消除感染源进行预防，仍然是继续努力减少传染病造成的人员和经济损失的基石。摄入受单核细胞增生李斯特菌污染的食物可导致新生儿、孕妇和免疫系统受损的人严重感染，有时甚至致命。我提出的研究将为理解单核细胞增生李斯特菌如何在表面的生物膜中持续存在于环境中奠定基础，例如食品加工中心的生物膜，在那里它可能是感染源。

DESCRIPTION (provided by applicant): Project Summary: This application details a five year research career development program designed to explore biofilm formation by the food-borne pathogen Listeria monocytogenes under the guidance of Dr. Roberto Kolter, Professor in the Department of Microbiology and Molecular Genetics at Harvard Medical School. Dr. Kolter is a leader in the field of microbial biofilm development and has an excellent track record of mentoring his trainees to positions as independent investigators. My long-term goal is to become an independent clinician-researcher. To this end, I have trained in both pediatric infectious diseases and biology. This proposal is designed to prepare me to be an independent researcher studying biofilm formation by L. monocytogenes. This field of study is very different from my prior research and my plan includes coursework in bacterial metabolism and bioinformatics. The gram-positive bacterium L. monocytogenes is a food-borne pathogen that causes severe, even fatal, infections in fetuses, newborns, and immunocompromised people. L. monocytogenes persisting on food preparation surfaces in the form of biofilms is a source of contamination that leads to listeriosis outbreaks. Biofilms are highly organized, matrixenclosed assemblages of microbial cells. Of particular relevance to both medicine and the food industry, biofilm bacteria are more resistant to detergents, biocides, and antibiotics than are individual, free-living bacteria. This makes decontamination of biofilm-coated surfaces particularly difficult. Although little is known about how Listeria forms biofilms, Listeria pathogenesis is well studied. As a result, a number of genetic and genomic tools are available. The experiments proposed herein are designed to determine: (1) what L. monocytogenes genes are required for biofilm formation using transposon and targeted mutagenesis, and (2) what are the physiological differences between individual free-living bacteria and biofilm-associated bacteria for L. monocytogenes using DNA microarray technology. Insights gained from these experiments should lead to new approaches to decontaminate biofilm-coated surfaces, and a better understanding of biofilms in general. Relevance: Prevention by eliminating sources of infection remains a cornerstone in the continued effort to decrease the human and economic toll of infectious diseases. Ingestion of food contaminated with Listeria monocytogenes can cause severe, sometimes fatal, infections in newborns, pregnant women and people with compromised immune systems. The research I have proposed will lay the foundation for understanding how Listeria monocytogenes persists in the environment in biofilms on surfaces, such as those in food processing centers, where it can be a source of infection.