Characterization of type 2 quorum sensing in Klebsiella pneumoniae and relationship with biofilm formation
Characterization of type 2 quorum sensing in Klebsiella pneumoniae and relationship with biofilm formation
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DOI：
10.1128/jb.187.8.2870-2880.2005
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发表时间：
2005-04-01
影响因子：
3.2
通讯作者：
Forestier, C
中科院分区：
文献类型：
--
作者：
Balestrino, D;Haagensen, JAJ;Forestier, C
群体感应是细菌通过使用被称为自诱导物的分泌的化学信号分子进行通信的过程。许多细菌物种通过这种机制调节多种生理功能的表达，以响应种群密度的变化。在这项研究中，观察到条件致病菌肺炎克雷伯氏菌分泌2型信号分子。从哈氏弧菌（Vibrioharveyi）中分离到一个luxS的同源基因，该基因是合成AI-2所必需的基因。pneumoniae基因组。哈维氏弧菌的生物测定表明，在K. pneumoniae和其补充大肠杆菌DH 5 α的luxS阴性表型的能力。在上清液中检测到自诱导物活性，并且通过定量逆转录-PCR分析检测到的特异性信使的最大表达发生在指数晚期。在补充有甘油的基本培养基中观察到最高水平的AI-2。为了确定luxS在定殖过程中的潜在作用，K.构建了pneumoniae luxS同基因突变体，并测试了其在体外非生物表面上形成生物膜和在鼠模型中定殖肠道的能力。在野生型菌株和luxS突变体之间的肠道定殖水平中没有观察到差异。生物膜结构的显微镜分析显示，luxS突变体能够形成成熟的生物膜，但在小菌落的发展能力降低，主要是在生物膜形成的早期步骤。这些数据表明，LuxS依赖性信号在K.肺炎。
Quorum sensing is a process by which bacteria communicate by using secreted chemical signaling molecules called autoinducers. Many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density by this mechanism. In this study, the opportunistic pathogen Klebsiella pneumoniae was observed to secrete type 2 signaling molecules. A homologue of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the K. pneumoniae genome. A V. harveyi bioassay showed the luxS functionality in K. pneumoniae and its ability to complement the luxS-negative phenotype of Escherichia coli DH5 alpha. Autoinducer activity was detected in the supernatant, and maximum expression of specific messengers detected by quantitative reverse transcription-PCR analysis occurred during the late exponential phase. The highest levels of AI-2 were observed in minimal medium supplemented with glycerol. To determine the potential role of luxS in colonization processes, a K. pneumoniae luxS isogenic mutant was constructed and tested for its capacity to form biofilms in vitro on an abiotic surface and to colonize the intestinal tract in a murine model. No difference was observed in the level of intestinal colonization between the wild-type strain and the luxS mutant. Microscopic analysis of biofilm structures revealed that the luxS mutant was able to form a mature biofilm but with reduced capacities in the development of microcolonies, mostly in the early steps of biofilm formation. These data suggest that a LuxS-dependent signal plays a role in the early stages of biofilm formation by K. pneumoniae.