Entamoeba coli, E. hartmanni, E. polecki,
Endolimax nana, and Iodamoeba buetschlii are generally
considered nonpathogenic, although they have been found in the stool of
patients presenting with diarrhea where no known pathogens were identified.
Their presence in stool can be an indicator of fecal contamination of a food
or water source, and does not rule-out the presence of other parasites. Entamoeba gingivalis is
also considered nonpathogenic, but is found in about 95% of patients with
gum disease and about 50% of patients with healthy gums.
E. coli, E. hartmanni, E. polecki, E. nana, and
I. buetschlii, identification is
made by observing cysts and/or trophozoites in stool specimens, both
concentrated wet mounts and permanent stained smears. Identification
of E. gingivalis is made by the finding of trophozoites in scrapings
of the gums and teeth. They may also be found in sputum in rare occasions.
As such, it is important to differentiate them from the
morphologically-similar trophozoites of E. histolytica, which may be
found in sputum from pulmonary abscesses.
As these six species are generally considered
nonpathogenic, there are currently no treatment recommendations for them.