Grimm D, Ludwig W F, Brandt B C, Michel R, Schleifer K H, Hacker J, Steinert M
Institut für Molekulare Infektionsbiologie, Universität Würzburg, Germany.
Syst Appl Microbiol. 2001 Apr;24(1):76-82. doi: 10.1078/0723-2020-00017.
Aquatic protozoa are natural hosts of the human pathogen Legionella pneumophila. The fluorescence labeled 16S rRNA-targeted oligonucleotide probe LEGPNE1 has recently been shown to specifically detect extracellular legionellae as well as intracellular legionellae parasitizing protozoa. In this study we designed oligonucleotide probes which are complementary to distinct regions of the 18S rRNA of the Legionella host organisms of the genera Hartmannella and Naegleria. The specificity of the probes, HART498 and NAEG1088, was tested by in situ hybridization of various laboratory reference strains. In order to evaluate the fluorescent probes for environmental studies three selected Legionella-positive cold water habitats were examined for the presence of these protozoa. Traditional culture methods followed by morphological identification revealed an almost consistent presence of Naegleria spp. in cold water habitats. Other protozoa species including Acanthamoeba spp., Echinamoeba spp., Hartmannella spp., Platyamoeba placida, Saccamoeba spp., Thecamoeba quadrilineata, and Vexillifera spp. were found sporadically. Concomitant analysis of the pH, conductivity and temperature of the water samples revealed no preference of Legionella or the respective protozoa for certain environmental conditions. The specificity of the newly designed 18S rRNA probes demonstrates that they are valuable and rapid tools for the identification of culturable environmental protozoa.
水生原生动物是人类病原体嗜肺军团菌的天然宿主。荧光标记的靶向16S rRNA的寡核苷酸探针LEGPNE1最近已被证明能特异性检测细胞外军团菌以及寄生于原生动物的细胞内军团菌。在本研究中，我们设计了与哈特曼氏阿米巴属和纳格里属军团菌宿主生物的18S rRNA不同区域互补的寡核苷酸探针。通过对各种实验室参考菌株进行原位杂交，测试了探针HART498和NAEG1088的特异性。为了评估这些荧光探针在环境研究中的作用，我们检查了三个选定的军团菌阳性冷水生境中这些原生动物的存在情况。传统培养方法结合形态学鉴定显示，纳格里属物种在冷水生境中几乎一直存在。其他原生动物物种，包括棘阿米巴属、棘变形虫属、哈特曼氏阿米巴属、扁平变形虫、囊变形虫属、四线变形虫和帆口虫属，只是偶尔被发现。对水样的pH值、电导率和温度进行的同步分析表明，军团菌或相应的原生动物对某些环境条件没有偏好。新设计的18S rRNA探针的特异性表明，它们是鉴定可培养环境原生动物的有价值且快速的工具。
