Molecular Microbial Ecology Group, Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
Appl Environ Microbiol. 2018 Feb 14;84(5). doi: 10.1128/AEM.02755-17. Print 2018 Mar 1.
Extreme habitats are not only limited to natural environments, but also exist in manmade systems, for instance, household appliances such as dishwashers. Limiting factors, such as high temperatures, high and low pHs, high NaCl concentrations, presence of detergents, and shear force from water during washing cycles, define microbial survival in this extreme system. Fungal and bacterial diversity in biofilms isolated from rubber seals of 24 different household dishwashers was investigated using next-generation sequencing. Bacterial genera such as , , and , known to include opportunistic pathogens, were represented in most samples. The most frequently encountered fungal genera in these samples belonged to , , and , also known to include opportunistic pathogenic representatives. This study showed how specific conditions of the dishwashers impact the abundance of microbial groups and investigated the interkingdom and intrakingdom interactions that shape these biofilms. The age, usage frequency, and hardness of incoming tap water of dishwashers had significant impact on bacterial and fungal community compositions. Representatives of spp. were found at the highest prevalence (100%) in all dishwashers and are assumed to be one of the first colonizers in recently purchased dishwashers. Pairwise correlations in tested microbiomes showed that certain bacterial groups cooccur, as did the fungal groups. In mixed bacterial-fungal biofilms, early adhesion, contact, and interactions were vital in the process of biofilm formation, where mixed complexes of bacteria and fungi could provide a preliminary biogenic structure for the establishment of these biofilms. Worldwide demand for household appliances, such as dishwashers and washing machines, is increasing, as is the number of immunocompromised individuals. The harsh conditions in household dishwashers should prevent the growth of most microorganisms. However, our research shows that persisting polyextremotolerant groups of microorganisms in household appliances are well established under these unfavorable conditions and supported by the biofilm mode of growth. The significance of our research is in identifying the microbial composition of biofilms formed on dishwasher rubber seals, how diverse abiotic conditions affect microbiota, and which key microbial members were represented in early colonization and contamination of dishwashers, as these appliances can present a source of domestic cross-contamination that leads to broader medical impacts.
极端生境不仅限于自然环境，也存在于人造系统中，例如洗碗机等家用电器。限制因素，如高温、高低 pH 值、高 NaCl 浓度、洗涤剂的存在以及洗涤循环中水流的剪切力，决定了微生物在这个极端系统中的生存。使用下一代测序技术研究了从 24 台不同家用洗碗机橡胶密封件中分离出的生物膜中的真菌和细菌多样性。在所研究的大多数样本中，都存在 、 和 等细菌属，这些细菌属包括机会性病原体。在这些样本中最常遇到的真菌属属于 、 和 ，也包括机会性病原体代表。这项研究展示了洗碗机的具体条件如何影响微生物群体的丰度，并研究了形成这些生物膜的种间和种内相互作用。洗碗机的年龄、使用频率和进入水的硬度对细菌和真菌群落组成有显著影响。 属的代表在所有洗碗机中都以最高的患病率（100%）存在，并且被认为是最近购买的洗碗机中最早定植的生物之一。在测试的微生物组中，某些细菌群体存在成对相关性，真菌群体也是如此。在混合细菌-真菌生物膜中，早期粘附、接触和相互作用对生物膜形成过程至关重要，其中细菌和真菌的混合复合物可以为这些生物膜的建立提供初步的生物发生结构。全球对洗碗机和洗衣机等家用电器的需求正在增加，免疫功能低下的个体数量也在增加。家用洗碗机的恶劣条件应该可以阻止大多数微生物的生长。然而，我们的研究表明，在这些不利条件下，家用设备中仍然存在持久的多极端耐受微生物群体，并且得到了生物膜生长方式的支持。我们研究的意义在于确定在洗碗机橡胶密封件上形成的生物膜的微生物组成、不同的非生物条件如何影响微生物群落以及在早期定植和污染洗碗机中存在哪些关键微生物成员，因为这些设备可能成为家庭交叉污染的来源，从而产生更广泛的医疗影响。
