Entamoeba coli (Nonpathogen)

Organism:
This organism belongs to the amebae, is a nonpathogen, and causes no disease.  Both the trophozoite (usual size, 15-50 µm) and cyst forms (usual size, 10-35 µm) can be found in clinical specimens.

   

Trophozoites

      

Cysts
                                                                                                         

Life Cycle:
Intestine, organisms passed in feces

Acquired:
Fecal-oral transmission via cyst form; contaminated food and water

Epidemiology:
Worldwide, primarily human-to-human transmission

Clinical Features:
None

Clinical Specimen:
Intestinal:  Stool

Laboratory Diagnosis:
Intestinal:  Ova and Parasite examination (concentration, permanent stained smear); identification based on morphology

Organism Description:
Trophozoite:  Unevenly arranged nuclear chromatin, eccentric karyosome, messy cytoplasm (may contain lots of debris)
Cyst:  May contain chromatoidal bars with sharp, jagged edges; mature cyst contains 8 nuclei (rarely more seen).

Laboratory Report:
Entamoeba coli (indicate cysts and/or trophozoites)

Treatment:
None

Control:
Improved hygiene, adequate disposal of fecal waste, adequate washing of contaminated fruits and vegetables

Comments:
E. coli can be differentiated from the Entamoeba histolytica/E. dispar group based on morphologic differences