EntamoebahistolyticaandOtherIntestinalAmebas 505(^3) Fig.9. 11
aGiardiaintestinalis(pathogenic):
trophozoites: 9–21!5–1 2 lm;
cysts: 8 – 14 !8–1 0 lm(seealsop. 4 78).
bDientamoebafragilis(apathogenicorfacultativelypathogenic):
trophozoites: 5 – 15 lm,3/4ofstageswithtwonuclei,therestwithone;
karyosomeconsistingoffourtosixgranules;
cysts:none.
cEntamoebahistolytica(pathogenic):
trophozoites:smallform(1) 10 – 20 lm,withEntamoebanucleusandsmallnumber
ofvacuolescontainingbacteria;largerform(2) 20 – 60 lm,withphagocytosed
erythrocytes;(3)cysts: 10 – 16 lm,onetofournuclei.Herebinuclearcystwithgly-
cogenvacuoleandcigarshapedchromidialbodiesand(4)atetranuclearcyst.
Entamoebadispar(apathogenic):morphologicallyidenticalwithE.histolytica
(seetext).
Entamoebahartmanni(5)(apathogenic):similartoE.histolytica,butsmaller.
Trophozoitesandcystsapproximately 3 – 10 lm.
dEntamoebacoli(apathogenic):
trophozoites:withEntamoebanucleus, 10 – 50 lm,inmostcasesnumerousva-
cuolescontainingbacteriaandparticles.Cysts: 15 – 25 lm,onetoeightnuclei,
chromidialbodiesslender,splinter-shaped.
eIodamoebabu ̈tschlii(apathogenic):
trophozoites: 6 – 20 lm,nucleuswithlargekaryosome,eithercentrallylocatedor
contiguouswiththenuclearmembrane.
Cysts: 5 – 18 lm,onenucleus,rarelytwo.
fEndolimaxnana(apathogenic):
trophozoites: 6 – 15 lm,nucleuswithkaryosome.
cysts:usuallyoval, 8 – 12 lmlong.
gMicrosporidia(pathogenic):
spores:verysmall(!), 1 – 3.5lmlongdependingonspecies,ovalshape;spores
oftennotstainedhomogeneouslybychromotropicstainingaccordingtoWeber
(seealsoFig.9.20c,p.539).
hBlastocystishominis(facultativelypathogenic?):
singlecells: 5 – 20 lm.
iCryptosporidiumspecies(pathogenic):
oocysts: 4 – 5 lm(seealsoFig.9. 14 a, p. 5 16 ).
jCyclosporacayetanensis(pathogenic):
oocysts: 4 – 5 lm,spherical,unsporulatedinfreshstool;aftersporulationtwospor-
ocystswithtwosporozoiteseach(seealsoFig.9. 14 a, p. 5 16 ).
kSarcocystisspecies(pathogenic):
sporocyst: 14! 9 lm;oocyst: 20! 13 lm.
lIsosporabelli(pathogenic):
oocyst: 20 – 33 !10– 19 lm.
9
Kayser, Medical Microbiology © 2005 Thieme