Szénási Z, Endo T, Yagita K, Nagy E
Department of Clinical Microbiology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
J Med Microbiol. 1998 Jan;47(1):5-16. doi: 10.1099/00222615-47-1-5.
Amphizoic small amoebic protozoa are capable of existing both in 'free-living' and in 'parasitic' form depending on the actual conditions. Two genera (Naegleria and Acanthamoeba) have become recognised as opportunist human parasites. Since the first description in 1965 of a lethal case of primary amoebic meningoencephalitis (PAM) caused by Naegleria, many more (mostly lethal) cases have been reported, while granulomatous amoebic encephalitis (GAE), as well as eye (keratinitis, conjunctivitis, etc.), ear, nose, skin and internal organ infections caused by Acanthamoeba have also occurred in rapidly increasing numbers. Both pathogenic and non-pathogenic species of Naegleria and Acanthamoeba are found worldwide in water, soil and dust, where they provide a potential source of infection. Successful differential diagnosis and appropriate (specific) therapy depends on precise laboratory identification of the 'free-living' amoebae. In most cases, isolation from the environment can be achieved, but identification and differentiation of the pathogenic and non-pathogenic strains is not easy. The methods presently available do not fulfil completely the requirements for specificity, sensitivity and reliability. Morphological criteria are inadequate, while thermophilic character, pH dependency and even virulence in infected mice, are not unambiguous features of pathogenicity of the different strains. More promising are molecular methods, such as restriction endonuclease digestion of whole-cell DNA or mitochondrial DNA, as well as iso-enzyme profile analysis after iso-electric focusing and staining for acid phosphatase and propionyl esterase activity. Use of appropriate monoclonal antibodies has also yielded promising results in the differentiation of human pathogenic and non-pathogenic strains. However, quicker, simpler, more specific and reliable methods are still highly desirable. The significance of endosymbiosis (especially with Legionella strains) is not well understood. The results of a systematic survey in Hungary for the isolation and identification of 'free-living' amoebae, including an investigation of the Hungarian amoebic fauna, the isolation of possibly pathogenic Naegleria strains and of some Acanthamoeba strains from eye diseases, as well as the finding of a case of endosymbiosis, are also reported here.
兼性小阿米巴原虫能够根据实际情况以“自由生活”和“寄生”两种形式存在。两个属（耐格里属和棘阿米巴属）已被确认为机会致病性人体寄生虫。自1965年首次描述由耐格里属引起的原发性阿米巴脑膜脑炎（PAM）致死病例以来，已报告了更多（大多为致死性）病例，而由棘阿米巴属引起的肉芽肿性阿米巴脑炎（GAE）以及眼部（角膜炎、结膜炎等）、耳部、鼻部、皮肤和内脏感染的病例数量也在迅速增加。耐格里属和棘阿米巴属的致病性和非致病性种类在世界各地的水、土壤和灰尘中均有发现，它们构成了潜在的感染源。成功的鉴别诊断和适当的（特异性）治疗取决于对“自由生活”阿米巴的精确实验室鉴定。在大多数情况下，可以从环境中分离出阿米巴，但致病性和非致病性菌株的鉴定和区分并不容易。目前可用的方法并未完全满足特异性、敏感性和可靠性的要求。形态学标准并不充分，而嗜热性、pH依赖性甚至在感染小鼠中的毒力，都不是不同菌株致病性的明确特征。更有前景的是分子方法，如全细胞DNA或线粒体DNA的限制性内切酶消化，以及等电聚焦和酸性磷酸酶及丙酰酯酶活性染色后的同工酶谱分析。使用适当的单克隆抗体在区分人类致病性和非致病性菌株方面也取得了有前景的结果。然而，仍然非常需要更快、更简单、更特异和更可靠的方法。内共生（特别是与军团菌菌株）的意义尚未得到充分理解。本文还报告了在匈牙利进行的一项系统调查结果，该调查旨在分离和鉴定“自由生活”阿米巴，包括对匈牙利阿米巴动物群的调查、从眼部疾病中分离可能致病的耐格里属菌株和一些棘阿米巴属菌株，以及发现一例内共生病例。
