Medical Microbiology

— Differentialdiagnosis.ItisimportanttodifferentiatetheE.histolytica/E.

disparcomplexfromintestinalepithelia,granulocytes,macrophages,and

fungiaswellasfromother,apathogenic,intestinalprotozoa(amebas:En-

tamoebacoli,E.hartmanni,E.polecki,Iodamoebabu ̈tschlii,Endolimax

nana;flagellates:Dientamoebafragilis,Enteromonashominis,Chilomastix

mesnili,Pentatrichomonashominis(Fig.9. 11 ).D.fragilisisclassifiedby

someauthorsaspotentiallypathogenic.Blastocystishominisisfrequently

foundinstoolsamples(Fig.9. 11 h):thisintestinalinhabitantisconsidered

afungusoraprotozoon;someauthorsascribeitacertainsignificanceas

causativeagentofdiarrhea.Itisimportanttorememberthatanumberof

drugsreducetheexcretionofintestinalprotozoa.

504 9 Protozoa

DifferentialDiagnosisofIntestinalProtozoa

g h i j k l

Unsporulated

Sporulated

Sporocyst

Oocyst

a b c d e f

1

2

3

Cy 4 5

sts

Trophozoit

es

Giardia

intesti-

nalis

Dient-

amoeba

fragilis

Entamoeba

histolytica

(1–4)

Entamoeba

hartmanni

(5)

Entamoeba

coli

Iod-

amoeba

bütschlii

Endo-

limax

nana

Microspora

spores

Blastocystis

hominis

Crypto-

sporidium

oocysts

Cyclospora

oocycts

Sarcocystis Isospora

belli oocyst

9

Kayser, Medical Microbiology © 2005 Thieme