What is the Difference Between E. histolytica and E. coli?

E. histolytica and E. coli are both species of Entamoeba, a group of amoebic parasites. However, they differ in their pathogenicity, structure, and other characteristics. Here are the main differences between E. histolytica and E. coli:

1. Pathogenicity: E. histolytica is a pathogenic protozoan responsible for causing amoebiasis, a foodborne disease that can be lethal. In contrast, E. coli is a non-pathogenic form that can live as a commensal in the large intestine and is excreted via stools.
2. Structural Differences:

• Trophozoite size: E. histolytica trophozoites measure 12-30 µm, while E. coli trophozoites measure 20-40 µm.
• Trophozoite motility: E. histolytica trophozoites have progressive, hyaline, fingerlike pseudopodia, while E. coli trophozoites have sluggish, nondirectional granular pseudopodia.
• Nucleus: E. histolytica trophozoites have 1-4 nuclei, while E. coli trophozoites have 2-8 nuclei.

1. Cyst Differences:

• Cyst size: E. histolytica cysts measure 10-15 µm, while E. coli cysts measure 15-25 µm.
• Cyst nuclei: E. histolytica mature cysts have 4 nuclei, while E. coli mature cysts have 8 nuclei.
• Peripheral chromatin: E. histolytica cysts have fine and dispersed peripheral chromatin, while E. coli cysts have coarse and clumped peripheral chromatin.

1. Chromatoid Bodies: E. histolytica cysts have rounded ends, while E. coli cysts have filamentous, thread-like, pointed ends.
2. Glycogen Mass: E. histolytica cysts have a visible glycogen mass in the uninucleate stage, while E. coli cysts have a large and visible glycogen mass in the binucleate stage.
3. Cytoplasmic Inclusions: E. histolytica cysts contain RBCs, leukocytes, and tissue debris but no bacteria, while E. coli cysts contain bacteria and other material but never RBCs.

It is essential to differentiate between E. histolytica and E. coli to accurately diagnose and treat amoebiasis. Various advanced tests are available to differentiate between pathogenic and nonpathogenic Entamoeba species, including isoenzyme analysis, antibody detection test, antigen detection test, immunochromatographic assays, and electron microscopy. DNA-based methods include polymerase chain reaction, microarray, and reverse line hybridization assay.

Comparative Table: E. histolytica vs E. coli

Here is a table comparing the differences between E. histolytica and E. coli:

Both E. histolytica and E. coli are eukaryotic single-celled organisms, belong to the genus Entamoeba, exist in two forms (trophozoite and cyst), are anaerobic, have a central nucleus with a prominent karyosome, and have storage food granules in the cytoplasm. They also share a fecal-oral route of entry and act as indicators of fecal contamination.