Freshwater plankton as a habitat for hygienically relevant microorganisms

地表水中的浮游生物提供了一个可以被生物膜定植的大表面。这些地方可以容纳与卫生有关的微生物，这些微生物可以通过浮游生物作为媒介传播。这一点已经在弧菌物种中得到证实，但对其他生物和淡水物种的了解要少得多，而初步结果表明了类似的情况。此外，这些生物可以进入有活力但不可培养（VBNC）的状态，用传统的培养方法无法检测到。当水被用于饮用水生产和/或娱乐用途时，这就构成了卫生风险。在这个项目中，目标生物对（活的和死的）当地典型浮游植物和浮游动物的定殖将在一个中营养型湖泊（Baldeneysee）进行调查。根据可能的输入地点和目标细菌事件，使用采样点进行定义的时空采样。目标生物是粪便指示剂（大肠杆菌、肠球菌、产气荚膜杆菌）和病原体（弯曲杆菌、铜绿假单胞菌、军团菌和气单胞菌），特别关注将使用分子生物学方法检测的VBNC状态。军团菌的生存能力将通过培养、直接活菌计数、膜完整性测定、FISH和实时PCR来确定。该项目的结果将有助于风险评估。

Plankton in surface waters provides a large surface which can be colonized by biofilms. These can harbour hygienically relevant microorganisms which can be transported by plankton organisms as vectors. This has been shown for Vibrio species, but much less is known about other organisms and for freshwater, while first results indicate a similar situation. Furthermore, the organisms can enter a viable but non culturable (VBNC) state and will not be detected by conventional culture methods. This poses a hygienic risk when the water is used for drinking water production and/or for recreational purposes. In this project, colonization of both (living and dead) locally typical phytoplankton and Zooplankton by target organisms will be investigated in a mesotrophic lake (Baldeneysee). Defined spatio-temporal sampling with sampling points according to possible input sites and events of target bacteria will be performed. Target organisms are fecal indicators (E. coli, enterococci, C. perfringens) and pathogens (Campylobacter spp., P. aeruginosa, Legionella spp. and Aeromonas spp.) Particular attention is payed to the VBNC state which will be detected using molecular biological methods. Viability will be determined by cultivation as well as by direct viable count, membrane integrity determination, FISH and real-time PCR for Legionella spp. Results of this project will contribute to risk assessment.