ZIEL-Institute for Food & Health, and Lehrstuhl für Mikrobielle Ökologie, Wissenschaftszentrum Weihenstephan, Technische Universität München, Weihenstephaner Berg 3, 85354, Freising, Germany.
Department of Microbiology, Immunology, & Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA.
Sci Rep. 2017 Dec 19;7(1):17821. doi: 10.1038/s41598-017-17570-0.
The human pathogen L. monocytogenes and the animal pathogen L. ivanovii, together with four other species isolated from symptom-free animals, form the "Listeria sensu stricto" clade. The members of the second clade, "Listeria sensu lato", are believed to be solely environmental bacteria without the ability to colonize mammalian hosts. To identify novel determinants that contribute to infection by L. monocytogenes, the causative agent of the foodborne disease listeriosis, we performed a genome comparison of the two clades and found 151 candidate genes that are conserved in the Listeria sensu stricto species. Two factors were investigated further in vitro and in vivo. A mutant lacking an ATP-binding cassette transporter exhibited defective adhesion and invasion of human Caco-2 cells. Using a mouse model of foodborne L. monocytogenes infection, a reduced number of the mutant strain compared to the parental strain was observed in the small intestine and the liver. Another mutant with a defective 1,2-propanediol degradation pathway showed reduced persistence in the stool of infected mice, suggesting a role of 1,2-propanediol as a carbon and energy source of listeriae during infection. These findings reveal the relevance of novel factors for the colonization process of L. monocytogenes.
人类病原体李斯特菌和动物病原体伊氏李斯特菌，以及从无症状动物中分离出的另外四种物种，形成了“李斯特菌严格意义上的属”分支。第二个分支“李斯特菌广义意义上的属”被认为是纯粹的环境细菌，没有能力在哺乳动物宿主中定植。为了鉴定导致食源性疾病李斯特菌病的病原体单核细胞增生李斯特菌感染的新决定因素，我们对两个分支进行了基因组比较，发现了 151 个在李斯特菌严格意义上的属中保守的候选基因。我们进一步在体外和体内研究了两个因素。一个缺乏 ATP 结合盒转运蛋白的突变体表现出对人 Caco-2 细胞的粘附和入侵缺陷。使用食源性李斯特菌感染的小鼠模型，与亲本菌株相比，突变菌株在小肠和肝脏中的数量减少。另一个具有缺陷 1,2-丙二醇降解途径的突变体在感染小鼠的粪便中持续存在减少，表明 1,2-丙二醇在感染期间是李斯特菌的碳和能源来源。这些发现揭示了新型因素在李斯特菌定植过程中的相关性。
