Parasitology Training Manual

Entamoeba coli

• Entamoeba coli is considered a non-pathogen at this time.
• The trophozoite and cyst of E. coli are both slightly larger than E. histolytica.
• The trophozoite measuring from 18 to 28 microns and larger has 1 nucleous containing a large diffuse karyosome. The peripheral chromatin is usually dense and irregular. The cytoplasm is usually rough with few to many ingested debris.
• In the wet mount it is usually impossible to differentiate between E. coli trophozoites and those of E. histolytica. A stained smear is required.
• The cysts measures from 12 to 25 microns and typically contains 8 nuclei with very diffuse karyosomes.
• The cyst may also contain chromatoidal bars with very irregular fragmented ends.
• Due to the size of the cyst and its density in a permanent stained smear it usually shrinks considerably.
• Hypernucleation is possible with as many as 16 or more nuclei present in one cyst.

Return to Entamoeba Introduction

The material on this site is owned by Scientific Image and Consulting
David M. Raymondo
MLT, CLS(m)
Professional Affiliation: Gamma-Dynacare Medical Laboratories, Ottawa, Ontario, Canada
Gamma-Dynacare is a Division of the Dynacare Health Group