Institute of Food Safety and Food Hygiene, Free University Berlin, Koenigsweg 69D, 14163, Berlin, Germany.
Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, 2205 East Mall, Vancouver, BC, V6T 1Z4, Canada.
Curr Top Microbiol Immunol. 2021;431:293-319. doi: 10.1007/978-3-030-65481-8_11.
Even though Campylobacter spp. are known to be fastidious organisms, they can survive within the natural environment. One mechanism to withstand unfavourable conditions is the formation of biofilms, a multicellular structure composed of different bacterial and other microbial species which are embedded in an extracellular matrix. High oxygen levels, low substrate concentrations and the presence of external DNA stimulate the biofilm formation by C. jejuni. These external factors trigger internal adaptation processes, e.g. via regulating the expression of genes encoding proteins required for surface structure formation, as well as motility, stress response and antimicrobial resistance. Known genes impacting biofilm formation will be summarized in this review. The formation of biofilms as well as the expression of virulence genes is often regulated in a cell density depending manner by quorum sensing, which is mediated via small signalling molecules termed autoinducers. Even though quorum sensing mechanisms of other bacteria are well understood, knowledge on the role of these mechanisms in C. jejuni biofilm formation is still scarce. The LuxS enzyme involved in generation of autoinducer-2 is present in C. jejuni, but autoinducer receptors have not been identified so far. Phenotypes of C. jejuni strains lacking a functional luxS like reduced growth, motility, oxygen stress tolerance, biofilm formation, adhesion, invasion and colonization are also summarized within this chapter. However, these phenotypes are highly variable in distinct C. jejuni strains and depend on the culture conditions applied.
尽管弯曲菌属被认为是一种挑剔的生物体，但它们可以在自然环境中存活。一种耐受不利条件的机制是生物膜的形成，生物膜是一种由不同细菌和其他微生物物种组成的多细胞结构，嵌入在细胞外基质中。高氧水平、低底物浓度和外部 DNA 的存在刺激了 C. jejuni 的生物膜形成。这些外部因素触发了内部适应过程，例如通过调节编码表面结构形成所需的蛋白质以及运动性、应激反应和抗微生物抗性的基因的表达。本文将总结影响生物膜形成的已知基因。生物膜的形成以及毒力基因的表达通常通过群体感应以细胞密度依赖的方式进行调节，群体感应是通过称为自诱导物的小信号分子介导的。尽管其他细菌的群体感应机制已经得到很好的理解，但关于这些机制在 C. jejuni 生物膜形成中的作用的知识仍然很少。C. jejuni 中存在参与生成自诱导物-2 的 LuxS 酶，但迄今为止尚未鉴定出自诱导物受体。缺乏功能性 luxS 的 C. jejuni 菌株的表型，如生长、运动性、耐氧应激能力、生物膜形成、黏附、侵袭和定植能力降低，也在本章中进行了总结。然而，这些表型在不同的 C. jejuni 菌株中差异很大，并且取决于所应用的培养条件。
