Intestinal Amebaecontinued Clinical Microbiology Review 237
AMEBA NUCLEUS TROPH CYST PATHOGENICITY OTHER
Entamoeba
hartmanni
Entamoeba
coli
Endolimax
nana
Iodamoeba
bütschlii
One of smallest
amebae.Only ameba
with just one
nucleus in cyst.Like E.
histolytica.Coarse,
irregular
peripheral
chromatin.
Eccentric
karyosome.No periph-
eral chro-
matin. Large,
irregular
karyosome.No peripheral
chromatin.
Large
karyosome
surrounded
by layer
of small
granules.Like E. histolytica, but 5–12 μm &
ingests bacteria.15–50 μm. Coarse cytoplasm with
many vacuoles & ingested bacteria.
Short, blunt, multiple pseudopods.
Sluggish nondirectional motility.2–12 μm. Single nucleus. Finely
granular vacuolated cytoplasm.
Blunt pseudopods. Sluggish,
nonprogressive motility.8–20 μm. Coarsely granular
cytoplasm with vacuoles & bacteria.
Blunt pseudopod. Sluggishly
progressive motility.Like E. histolytica,but smaller. 5–9 μm.Round. 10–35 μm. 2–8 nuclei.
Occasional chromatoid bodies with
splintered ends. May have glycogen
vacuoles.5–10 μm. Round to oval. Usually
4 nuclei. No chromatoid bodies. May
have poorly defined glycogen mass.5–20 μm. Ovoid. 1 nucleus. Prominent
glycogen vacuole. “Iodine cyst.”Nonpathogenic.Nonpathogenic.Nonpathogenic.Nonpathogenic.continued...