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Aug 23, 2023 · On initial microscopy, the cyst of Entamoeba coli typically has eight nuclei, while Entamoeba histolytica typically has four. The peripheral chromatin is coarse and irregularly clumped for Entamoeba coli and fine, evenly distributed for Entamoeba histolytica.
- Akhlema Haidar, Orlando De Jesus
- 2023/08/23
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. Entamoeba coli is the only Entamoeba species found in humans that has more than four nuclei in the cyst stage. The nuclei may be seen in unstained as well as stained specimens.
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.
Immature cysts typically have a large glycogen vacuole and two nuclei. Mature cysts have eight nuclei, with hypernucleate forms having 16 or more nuclei. The presence of an Entamoeba cyst in human stool with more than four nuclei is pathognomonic for E. coli (Ash and Orihel, 2007).
Although the concentration technique is helpful in demonstrating cysts, the use of permanently stained smears (trichrome or iron hematoxylin) is an important method for recovery and identification of Entamoeba species.
- R. Fotedar, D. Stark, N. Beebe, D. Marriott, J. T. Ellis, J. Harkness
- 10.1128/CMR.00004-07
- 2007
- Clin Microbiol Rev. 2007 Jul; 20(3): 511-532.
Aug 23, 2023 · Mature Entamoeba coli Cyst. This photomicrograph of an iron-hematoxylin-stained specimen revealed the presence of a mature Entamoeba coli cyst, which contained five visible nuclei, each with its eccentrically located karyosome and peripherally located chromatin.
Cysts of Entamoeba hartmanni are similar to those of E. histolytica but smaller, measuring 5-10 µm. Mature cysts contain four nuclei that possess a small, discrete centrally-located karyosome and evenly-distributed peripheral chromatin. Cysts may not be visible in unstained specimens.
