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Aug 23, 2023 · Entamoeba coli, similar to other Entamoeba specifies, has three distinct morphological forms: trophozoite, pre-cystic stage, and cystic stage. The trophozoite form, which measures 20 to 25 μm, is minimally mobile. [23]
E. coli cysts in concentrated wet mounts. Cysts of Entamoeba coli are usually spherical but may be elongated and measure 10–35 µm. Mature cysts typically have 8 nuclei but may have as many as 16 or more.
E. coli has cysts in size up to 10 to 35 micrometers, the shape is irregular, oval with a shell-like appearance that is more uniformed compared to E. histolytica, and has up to eight nuclei in the cyst compared to the four nuclei of E. histolytica.
The cysts and trophozoites of E. coli can be distinguished from those of the pathogenic E. histolytica on the basis of nuclear morphology and cyst size. Whereas E. histolytica cysts usually have fewer than five nuclei and are 10–15 µm in diameter, the cysts of E. coli are greater than 15 µm and often have five to eight nuclei. 179–181
Pathogenic Entamoeba species must be differentiated from other intestinal protozoa such as the nonpathogenic amebae (Entamoeba coli, E. hartmanni, E. gingivalis, Endolimax nana, Iodamoeba buetschlii) and the flagellate Dientamoeba fragilis. Morphologic differentiation among these is possible, but potentially complicated, based on morphologic ...
The life cycle of E. histolytica consists of an infectious quadri-nucleate cyst and an invasive trophozoite form. The infectious cyst form is 10 to 16 μm in diameter and contains four, in mature cysts, or fewer nuclei, in immature forms ( Figure 263-1A ).
Structure. The trophozoite is 10 to 60 µm in diameter, ameboid, actively motile, and often erythrophagocytic. In stained specimens, the nucleus has a central karyosome with finely beaded peripheral chromatin. The cyst form is rounded, 10 to 20 µm in diameter, with one to four nuclei showing the characteristic appearance.
