Ragavan Anitamalar Devi, Govind Suresh Kumar
Department of Parasitology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia,
Parasitol Res. 2015 Mar;114(3):1163-6. doi: 10.1007/s00436-014-4296-8. Epub 2015 Jan 23.
Dientamoeba fragilis, a trichomonad parasite is usually found in the gastrointestinal tract of human, and it is known to be the cause for gastrointestinal disease. The parasite is globally distributed and mostly found in rural and urban areas. The parasite is found in humans and nonhuman primates such as the macaques, baboons, and gorillas. Often, the parasite is confused with another largely found organism in stools called Blastocystis sp. especially when seen directly under light microscopy on culture samples containing both parasites. Both sometimes are seen with two nuclei with sizes tending to be similar which complicates identification. Stools were collected fresh from nine previously diagnosed persons infected with D. fragilis who also were found to be positive for Blastocystis sp. Samples were then cultured in Loeffler's medium and were stained with Giemsa, iron hematoxylin, and modified Fields' (MF) stain, respectively. D. fragilis was differentiated from Blastocystis sp. when stained with MF stain by the presence of a thinner outer membrane with clearly demarcated nuclei in the center of the cell whilst Blastocystis sp. had a darker and thicker stained outer membrane with the presence of two nuclei. The staining contrast was more evident with modified Fields' stain when compared with the other two. The simplicity in preparing the stain as well as the speed of the staining procedure make MF stain an ideal alternate. The modified Fields' stain is faster and easier to prepare when compared to the other two stains. MF stain provides a better contrast differentiating the two organisms and therefore provides a more reliable diagnostic method to precisely identify one from the other especially when cultures show mixed infections.
脆弱双核阿米巴，一种毛滴虫寄生虫，通常存在于人类胃肠道中，已知是胃肠道疾病的病因。这种寄生虫在全球范围内分布，多见于农村和城市地区。它存在于人类和猕猴、狒狒、大猩猩等非人类灵长类动物体内。通常，这种寄生虫会与粪便中另一种常见的生物体——芽囊原虫混淆，尤其是在含有这两种寄生虫的培养样本的光学显微镜直接观察下。有时两者都可见两个大小相近的细胞核，这使得鉴别变得复杂。从9名先前被诊断感染脆弱双核阿米巴且同时被发现芽囊原虫呈阳性的患者新鲜采集粪便样本。然后将样本分别在吕氏培养基中培养，并用吉姆萨染色、铁苏木精染色和改良菲尔德氏（MF）染色。当用MF染色时，脆弱双核阿米巴与芽囊原虫得以区分，前者细胞中心有更薄的外膜且细胞核界限清晰，而芽囊原虫的外膜染色更深更厚且有两个细胞核。与另外两种染色相比，改良菲尔德氏染色的染色对比度更明显。制备该染色剂的简便性以及染色过程的速度使MF染色成为理想的替代方法。与另外两种染色剂相比，改良菲尔德氏染色制备更快且更容易。MF染色能更好地区分这两种生物体，因此提供了一种更可靠的诊断方法，能准确地将两者区分开来，尤其是在培养显示混合感染的情况下。
