Ariyadasa Sujani, van Hamelsveld Sophie, Taylor William, Lin Susan, Sitthirit Panan, Pang Liping, Billington Craig, Weaver Louise
Institute of Environmental Science and Research, 27 Creyke Road, Ilam, Christchurch 8041, New Zealand.
Pathogens. 2024 Aug 7;13(8):665. doi: 10.3390/pathogens13080665.
Free-living amoebae (FLA) are common in both natural and engineered freshwater ecosystems. They play important roles in biofilm control and contaminant removal through the predation of bacteria and other taxa. Bacterial predation by FLA is also thought to contribute to pathogen dispersal and infectious disease transmission in freshwater environments via the egestion of viable bacteria. Despite their importance in shaping freshwater microbial communities, the diversity and function of FLA in many freshwater ecosystems are poorly understood. In this study, we isolated and characterized FLA from two groundwater sites in Canterbury, New Zealand using microbiological, microscopic, and molecular techniques. Different methods for groundwater FLA isolation and enrichment were trialed and optimized. The ability of these isolated FLA to predate on human pathogen was assessed. FLA were identified by 18S metagenomic amplicon sequencing. Our study showed that spp. (including ) and were the main FLA species present in both groundwater sites examined. While most of the isolated FLA co-existed with , the FLA populations in the co-culture experiments predominantly consisted of , spp., spp., , spp., and spp. These observations suggest that FLA may have the potential to act as reservoirs for in Canterbury, New Zealand groundwater systems and could be introduced into the local drinking water infrastructure, where they may promote the survival, multiplication, and dissemination of . This research addresses an important gap in our understanding of FLA-mediated pathogen dispersal in freshwater ecosystems.
自由生活阿米巴（FLA）在自然和人工淡水生态系统中都很常见。它们通过捕食细菌和其他分类群在生物膜控制和污染物去除中发挥重要作用。FLA对细菌的捕食也被认为通过排出有活力的细菌促进了淡水环境中病原体的传播和传染病的传播。尽管它们在塑造淡水微生物群落方面很重要，但许多淡水生态系统中FLA的多样性和功能仍知之甚少。在本研究中，我们使用微生物学、显微镜和分子技术从新西兰坎特伯雷的两个地下水位点分离并鉴定了FLA。我们试验并优化了不同的地下水FLA分离和富集方法。评估了这些分离出的FLA对人类病原体的捕食能力。通过18S宏基因组扩增子测序鉴定了FLA。我们的研究表明，在两个被检测的地下水位点中，棘阿米巴属物种（包括卡氏棘阿米巴）和嗜热四膜虫是主要的FLA物种。虽然大多数分离出的FLA与嗜肺军团菌共存，但在共培养实验中的FLA种群主要由棘阿米巴属、嗜热四膜虫属物种、波列基内变形虫、微小内蜒阿米巴、结肠内阿米巴和哈氏内阿米巴组成。这些观察结果表明，在新西兰坎特伯雷的地下水系统中，FLA可能有潜力作为嗜肺军团菌的宿主，并可能被引入当地的饮用水基础设施，在那里它们可能促进嗜肺军团菌的存活、繁殖和传播。这项研究填补了我们在理解淡水生态系统中FLA介导的病原体传播方面的一个重要空白。
