Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
Animal Sciences Department, University of Nebraska, Lincoln, NE 68588, USA.
J Med Microbiol. 2013 Jan;62(Pt 1):25-35. doi: 10.1099/jmm.0.049742-0. Epub 2012 Sep 13.
Listeria monocytogenes is a food-borne pathogen responsible for the disease listeriosis. The infectious process depends on survival in the high bile-salt conditions encountered throughout the gastrointestinal tract, including the gallbladder. However, it is not clear how bile-salt resistance mechanisms are induced, especially under physiologically relevant conditions. This study sought to determine how the L. monocytogenes strains EGDe (serovar 1/2a), F2365 (serovar 4a) and HCC23 (serovar 4b) respond to bile salts under anaerobic conditions. Changes in the expressed proteome were analysed using multidimensional protein identification technology coupled with electrospray ionization tandem mass spectrometry. In general, the response to bile salts among the strains tested involved significant alterations in the presence of cell-wall-associated proteins, DNA repair proteins, protein folding chaperones and oxidative stress-response proteins. Strain viability correlated with an initial osmotic stress response, yet continued survival for EGDe and F2365 involved different mechanisms. Specifically, proteins associated with biofilm formation in EGDe and transmembrane efflux pumps in F2365 were expressed, suggesting that variations exist in how virulent strains respond and adapt to high bile-salt environments. These results indicate that the bile-salt response varies among these serovars and that further research is needed to elucidate how the response to bile salts correlates with colonization potential in vivo.
李斯特菌是一种食源性病原体，可导致李斯特菌病。感染过程取决于在整个胃肠道（包括胆囊）中遇到的高胆汁盐条件下的存活能力。然而，目前尚不清楚如何诱导胆汁盐抗性机制，特别是在生理相关条件下。本研究旨在确定 L. monocytogenes 菌株 EGDe（血清型 1/2a）、F2365（血清型 4a）和 HCC23（血清型 4b）如何在厌氧条件下对胆汁盐作出反应。使用多维蛋白质鉴定技术与电喷雾电离串联质谱联用分析表达的蛋白质组。总的来说，测试菌株对胆汁盐的反应涉及细胞壁相关蛋白、DNA 修复蛋白、蛋白质折叠伴侣和氧化应激反应蛋白的存在发生显著改变。菌株的存活能力与初始渗透胁迫反应相关，但 EGDe 和 F2365 的持续存活涉及不同的机制。具体而言，在 EGDe 中与生物膜形成相关的蛋白和 F2365 中与跨膜外排泵相关的蛋白被表达，这表明毒力菌株对高胆汁盐环境的反应和适应存在差异。这些结果表明，这些血清型之间的胆汁盐反应存在差异，需要进一步研究阐明胆汁盐的反应与体内定植潜力的相关性。
