Braganra S M, Azevedo N F, Simões L C, Keevil C W, Vieira M J
Centro de Engenharia Biológica, Universidade do Minho, 4700-057 Braga, Portugal.
Water Sci Technol. 2007;55(8-9):387-93. doi: 10.2166/wst.2007.282.
A fluorescently labelled peptide nucleic acid (PNA) probe has been applied for the in situ detection of Helicobacter pylori in drinking water biofilms. The method was originally applied to real pipe samples removed from a drinking water distribution system (DWDS) but the curvature and the heavy fouling of the pipes prevented an accurate detection of the bacterium by epifluorescence microscopy. Therefore, two semi-circular flow cells were placed in a bypass of the DWDS, and coupons with up to 72 days of exposure were regularly sampled and analysed for the presence of H. pylori. In the flat surfaces of the coupons, it was possible to sparsely detect cells exhibiting similar morphology to H. pylori that were emitting the PNA probe fluorescent signal. Coupons were also visualised under the microscope before the hybridisation procedure to serve as negative controls and ensure the validity of the method. This work corroborates the findings already published elsewhere that this bacterium might be present in DWDS biofilms. The method requires, however, highly trained personnel for an accurate detection of the pathogen and will need simplification before being routinely used in standard water analysis laboratories.
一种荧光标记的肽核酸（PNA）探针已用于原位检测饮用水生物膜中的幽门螺杆菌。该方法最初应用于从饮用水分配系统（DWDS）中取出的实际管道样本，但管道的曲率和严重污垢阻碍了通过落射荧光显微镜准确检测该细菌。因此，将两个半圆形流动池放置在DWDS的旁路中，并定期对暴露长达72天的试片进行采样和分析，以检测幽门螺杆菌的存在。在试片的平面上，可以稀疏地检测到发出PNA探针荧光信号、形态与幽门螺杆菌相似的细胞。在杂交程序之前，还在显微镜下观察试片作为阴性对照，以确保该方法的有效性。这项工作证实了其他地方已发表的研究结果，即这种细菌可能存在于DWDS生物膜中。然而，该方法需要训练有素的人员才能准确检测病原体，并且在常规用于标准水分析实验室之前需要简化。
