Mirjalali Hamed, Niyyati Maryam, Abedkhojasteh Hoda, Babaei Zahra, Sharifdini Meysam, Rezaeian Mostafa
Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Dept. of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Iran J Parasitol. 2013 Oct;8(4):530-5.
Acanthamoeba genus is introduced as opportunistic and cosmopolitan parasite. Monkey and wistar rat are appropriate models for experimental study on Acanthamoeba infection. In this study Acanthamoeba spp. were isolated from hot spring (HS), windows dust (WD) and a corneal sample of keratitis patient (KP) and their pathogenicity surveyed by in vitro and in vivo tests.
Isolates of Acanthamoeba were cultivated axenically for 12 months in PYG medium. Overall, 30 wistar rats, in 6 equal groups were used for developing experimental Acanthamoeba keratitis (AK) and Granulomatous Amoebic Encephalitis (GAE). The Keratitis and Granulomatous Encephalitis experiments were performed by intrastromal and intranasal inoculation of Acanthamoeba cysts, respectively. Pathogenicity of the three isolates was also evaluated by in vitro test using osmotolerance and temperature tolerance assays. Identification of genotypes were performed by PCR technique and sequencing.
None of the isolates could perform AK and GAE in wistar rats, although all isolates were described as T4 genotype. Isolates obtained from KP and WD could grow only in 30 °C, but not in 37 °C and 40 °C. On the other hand, HS isolate grew in 30 °C and 37 °C but not in 40 °C. Moreover, all of isolate grew in 0.5 M mannitol but not in 1 M and 1.5 M.
T4 isolates with a long-term axenic culture and different factors related to host and parasite may play role in pathogenicity of these free-living amoebae.
棘阿米巴属被认为是一种机会性和世界性分布的寄生虫。猴子和Wistar大鼠是棘阿米巴感染实验研究的合适模型。在本研究中，从温泉（HS）、窗户灰尘（WD）和一名角膜炎患者的角膜样本（KP）中分离出棘阿米巴，并通过体外和体内试验对其致病性进行了调查。
将棘阿米巴分离株在PYG培养基中无菌培养12个月。总共30只Wistar大鼠被分为6个相等的组，用于建立实验性棘阿米巴角膜炎（AK）和肉芽肿性阿米巴脑炎（GAE）。角膜炎和肉芽肿性脑炎实验分别通过角膜基质内和鼻内接种棘阿米巴囊肿进行。还通过渗透压耐受性和温度耐受性试验的体外试验评估了这三种分离株的致病性。通过PCR技术和测序进行基因型鉴定。
尽管所有分离株均被描述为T4基因型，但没有一个分离株能在Wistar大鼠中引起AK和GAE。从KP和WD获得的分离株仅能在30°C生长，而不能在37°C和40°C生长。另一方面，HS分离株能在30°C和37°C生长，但不能在40°C生长。此外，所有分离株都能在0.5M甘露醇中生长，但不能在1M和1.5M中生长。
长期无菌培养的T4分离株以及与宿主和寄生虫相关的不同因素可能在这些自由生活阿米巴的致病性中起作用。
