Current Status of Acanthamoeba in Iran: A Narrative Review Article

Background:

Free-living amoebae belonging to the genus Acanthamoeba have an environmental distribution. Amoebic keratitis due to these protozoan parasites continue to rise in Iran and worldwide. In Iran, there are various researches regarding both morphological and molecular identification of Acanthamoeba spp. in environmental and clinical samples. However, there is no thorough review about Acanthamoeba genotypes and their distribution in environmental sources such as water, dust and biofilm in Iran. Besides, according to increasing cases of Amoebic keratitis in the region awareness regarding the pathogenic potential of these sight-threatening amoebae is of utmost importance.

Methods:

We conducted a thorough review based on the database sources such as MEDLINE, PubMed and Google scholar. No restrictions were placed on study date, study design or language of publication. We searched all valuable and relevant information considering the occurrence of the Acanthamoeba in both environmental and clinical samples.

Results:

According to our thorough review Acanthamoeba belonging to T4 genotype is the most prevalent type strain in environmental and clinical samples in several regions in Iran and worldwide, however, there are reports regarding Acanthamoeba belonging to other genotypes such as T2, T3, T5, T6 and T11 and the mentioned point could leads us to more researches with the goal of presenting the real genotype dominance of Acanthamoeba and related disease in the country.

Conclusion:

Overall, the present review will focus on present status of genotypes of Acanthamoeba in Iran during recent years.     

棘阿米巴分类与虫种鉴定方法的研究进展

棘阿米巴是致病性的自由生活阿米巴,因其特殊的形态特征在属级分类不难,但仅根据形态学特征鉴定到种较为困难。本文就国内外对棘阿米巴分类与虫种鉴定方法的研究进展进行综述。     

Heidelberg Retina Tomograph II Findings of Acanthamoeba Keratitis

Purpose: Heidelberg retina tomograph II (HRTII) examination was performed with cornea module in one patient with Acanthamoeba keratitis (AK) to provide images detailing characteristic findings of the disease. Methods: A 34-year-old woman presented with clinical signs and symptoms of AK. HRTII with cornea module was performed and the patient underwent laboratory investigations. Results: HRTII examination with cornea module revealed numerous 20–26-μ m diameter high-contrast round particles within the corneal epithelium and anterior stroma, resembling Acanthamoeba cysts. Stellate cells as well as ovoid irregular objects, possibly inflammatory cells, trophozoites, altered cysts, or activated keratocytes, were also present in the area of stromal infiltrates. Laboratory investigations confirmed the diagnosis of AK. Conclusions: HRTII cornea module can be helpful in the diagnosis of AK by identifying acanthamoeba cyst-like structures in the cornea. This technique also has potential uses in monitoring the efficiency of anti-infective treatment.     

棘阿米巴土壤分离株CB/S1的线粒体DNA限制性片段长度多态性

[目的]观察棘阿米巴土壤分离株CB/S1的线粒体DNA限制性片段长度多态性(RFLP)。[方法]从棘阿米巴CB/S1提取线粒体DNA用EcoRI酶切,与土壤分离株CJY/S4比较观察限制性片段长度多态性。用地衣红-卡红染色观察棘阿米巴内共生细菌。[结果]棘阿米巴土壤分离株CB/S1线粒体DNARFLP与CJY/S4相比除了额外的片段(extra bands),两个分离株具有相同的片段模式。经地衣红染色观察CB/S1内共生细菌呈黑色、棒状、不规则的分布在胞质内。[结论]额外的片段表明棘阿米巴CB/S1内含有内共生细菌的环状DNA,并且除了内共生细菌的存在棘阿米巴CB/S1与土壤分离株CJY/S4具有密切的亲缘关系。线粒体DNA限制性片段长度多态性是棘阿米巴分类及发现内共生细菌的简便而有效的方法。     

多噬棘阿米巴电泳核型初报

应用脉冲电场凝胶电泳(PFGE)方法,对一种致病性自由生活阿米巴——多噬棘阿米巴的染色体DNA大分子进行分离,并对该寄生原虫的电泳核型进行了观察。所得到的初步结果显示,该虫株的染色体数目在10条以上。在电泳凝胶上可分辨的最大染色体接近2mb,最小的染色体在200kb左右。     

Dual Targeting of Function–Structure for Effective Killing of Pathogenic Free-Living Amoebae

Here we discuss the potential value of targeting both the hardy structure of the cyst state of the parasite, in addition to the active trophozoite form, to provide target-directed inhibition as a viable drug strategy in the effective eradication of parasites.     

Corneal biopsy in microbial keratitis

Presumed microbial keratitis in the absence of a specific microbiological diagnosis is a particularly difficult clinical problem. Corneal biopsy may provide the diagnosis when corneal scrapings have been negative. We present two cases in which corneal biopsy was helpful and discuss the role of corneal biopsy in the management of chronic keratitis     

棘阿米巴性角膜炎行角膜移植术的临床观察

目的 回顾性分析13例棘阿米巴性角膜溃疡行角膜移植手术治疗的临床效果.方法 临床诊断棘阿米巴性角膜炎患者13例,其中6例行板层角膜移植术,7例行穿透性角膜移植术,术后继续应用抗阿米巴药物1～3个月.结果 术后随访6个月至2年,感染均得到控制.术后视力情况,LK术后指数的1例,0.02 ～ 0.1的3例,0.12～0.3的2例,PK术后小于0.02的3例,0.02～0.1的2例,0.12～0.3的2例.结论 棘阿米巴性角膜炎在药物不能控制的情况下,行角膜移植术可有效控制炎症,根据病灶的深度合理选择术式,术后可获得良好的治疗效果.同时术后辅以抗阿米巴药物的治疗可以起到辅助治疗的目的.