摘要：兩類自營性阿米巴原蟲 - Acanthamoeba 與Hartmannella vermiformis - 是細菌類病原菌（如：Mycobacterium, Pseudomonas 與 Legionella）的天然宿主，此外，此二類原蟲也可導致人類疾病。傳統上採用培養法定量自營性原蟲有許多限制，而結合分子生物學 (如：quantitative polymerase chain reaction, qPCR) 可達到具特異性且快速定量之目的。然目前非常欠缺量化環境中Acanthamoeba 與Hartmannella vermiformis 的學術報告，對其在環境中的流佈、暴露風險以及影響其濃度變化之因子所知也相當有限，亦無從得知其濃度變化是否對寄生其體內之病原菌（如：Legionella）的影響。本計畫將以三年為期程探究上述議題。第一年將先建立可定量環境中Acanthamoeba 與H. vermiformis 之qPCR 方法。第二年則將著手評估冷卻水與熱水供應系統中Acanthamoeba與H. vermiformis 在水體及生物膜中之流佈、相關環境因子、以及其對Legionella 族群之影響。第三年則針對廢水系統，評估在不同處理階段Acanthamoeba 與H. vermiformis 之流佈，並探究其與水中重金屬及相關環境因子之關連性。最後將彙整冷卻水、熱水、以及廢水數據，評估顯著影響Acanthamoeba 與H. vermiformis 之因子，並分析Acanthamoeba 與H. vermiformis在不同環境與基質內檢出率與濃度之差異性。預期未來可應用本研究所建立之qPCR 方法，定量各類環境中Acanthamoeba 與H.vermiformis。另對於易爆發院內感染的醫院、老人安養場所、分佈於工業界與都市巷弄間的冷卻水塔、以及廢水處理，本研究所分析之影響因子數據將可應用於實務管理層面，提供控制Acanthamoeba 與H. vermiformis 之策略，此將有助於抑制此二類致病原蟲的感染風險，也有助於控制依其滋生並增長毒性的其他病原性細菌之威脅。
Abstract: Acanthamoeba and Hartmannella vermiformis, two kinds of free-living amoebae (FLA),are natural hosts of bacterial pathogens (e.g., Mycobacterium, Pseudomonas, and Legionella)and associated with human diseases. Traditionally, quantification of FLA based on cultivationmethod has limitations. On the other hand, the molecular biology techniques (e. g.,quantitative polymerase chain reaction, qPCR) may be more specific and rapid. However, theresearches about the molecular quantification of amoebic Acanthamoeba and H. vermiformisand the factors affecting their distribution in environments are limited. Also, the influence ofamoebic density change on associated parasitic pathogens (i.e. Legionella) remains unclear.Therefore, this project will first establish the qPCR methods for quantification ofenvironmental Acanthamoeba and H. vermiformis, as the first-year study purpose. The secondyear will begin to assess the abundance of Acanthamoeba and H. vermiformis in water andbiofilms derived from cooling towers and hot water supply systems. Statistically significantenvironmental factors as well as the influence of amoebic density on the population ofLegionella will also be assessed. The third year will focus on the investigation of wastewatertreatment plants. Distributions and quantification of Acanthamoeba and H. vermiformis atdifferent processing stages will be assessed; their associations with 15 heavy metals and otherenvironmental factors will also be studied. Finally, the data yielded from cooling towers, hotwater supply systems and wastewater treatment plants will be collectively analyzed. Thefactors significantly affecting the abundance of Acanthamoeba and H. vermiformis as well asthe differences of amebic concentrations and positive rates between these two FLAs indifferent systems and sample types will also be determined.It is expected that the qPCR methods constructed in this study could also be applied toquantify Acanthamoeba and H. vermiformis in water and biofilms of other kinds ofenvironments. In addition, the significantly associated environmental factors determined inthis study may be adopted as references in planning an effective control measure ofenvironmental Acanthamoeba and H. vermiformis for the facilities such as hospitals, nursinghomes, sewage treatment plants, and cooling towers located in cities and industries, whichwill be helpful in controlling the exposure and potentially infectious risk to these two FLAsand their parasitic pathogens.