INTESTINAL (Protozoa) AND LIVER PARASITES
MICROSPOREA Order: Microsporida

ENTEROCYTOZOON BIENEUSI

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Enterocytozoon bieneusi: life cycle.
Microsporidia are obligate, intracellular,
spore-forming protozoa known to infect many animals.
They are phylogenetically very ancient protozoa.
Intestinal infection with Enterocytozoon bieneusi are increasingly recognized
in patients with AIDS and chronic diarrhea where the prevalence is about 23-33%.
The pathogenic role of E.bieneusi is still controversial.

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Enterocytozoon bieneusi: spores are the infective stage of the protozoa.
They are excreted with feces and can be recovered
also in duodenal and biliary fluid or BAL.
Spores are oval in shape but are difficult to differentiate from bacteria.
(Wet mount).

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E.bieneusi: identification of spores in feces is actually possible with
a modified trichrome stain that stain spores in red.
(E.bieneusi spores, Weber modified trichrome stain).

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E.bieneusi: spores of E.bieneusi have an ellipsoidal structure staining
pink-red with a small polar or central non-stained zone.
They measure 0.7-1 by 1.08-1.64 µm.
(E.bieneusi spores, Weber modified trichrome stain).

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E.bieneusi: routine standard stains such Giemsa or Gram
are not adequate for detecting spores in presence of bacteria.
Giemsa stain is useful in staining duodenal fluid where both spores and
developing stages can be observed.
(Spores with Giemsa).

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E.bieneusi: Fluorescent probes (Calcofluor, Uvitex B) have affinity to chitin,
a component of the spore wall.
Microsporidian spores appear as oval organisms bright blue on a dark background.
(E.bieneusi spores, Calcofluor stain, UV with A filter, BP: 340-380 µm).

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E.bieneusi:The association of Calcofluor with DAPI (specific for DNA) give more
information on spore morphology: most spores contain an inner bright spot
of fluorescence corresponding to nuclear material.
(Spores with Calcofluor+DAPI).

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E.bieneusi and E.intestinalis: two monoclonal antibodies specific for E. bieneusi spores (1.3 x 0.7 mm) (Photo 1) and E. intestinalis (Photo 2) spores (1.7 x 1.0 - 1.1 mm) were developed to screen stools by indirect immunofluorescence assay. Differentiation between the two intestinal microsporidia is required for an adequate therapy management. E. intestinalis infections are treated with albendazole, while fumagillin has been shown to be effective for eradicating E. bieneusi. Thus, species identification is important for defining the appropriate treatment.

Reference: Simple species diagnosis of human intestinal microsporidia by an immunofluorescence test using specific monoclonal antibodies : an evaluation study in two hospitals in France. M. Thellier, I. Accoceberry , I. Desportes, S. Biligui, E. Bart-Delabesse, C. Ripert, M. Danis, A. Datry. First United Workshop on Microsporidia from Invertebrate and Vertebreate Hosts (NATO). July 12-15,2004.

Monoclonal antibodies for the coprological diagnosis of microsporidiosis

99,5 Kb

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E.bieneusi: intracellular organisms can be observed in exfoliated cells
obtained from duodenal fluid.
Spores within the cytoplasm of intestinal cells, Giemsa stain.

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E.bieneusi: intracellular organisms can be observed in exfoliated cells
obtained from duodenal fluid.
Spores within the cytoplasm of intestinal cells, Giemsa stain.

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E.bieneusi: intracellular organisms can be observed in exfoliated cells
obtained from duodenal fluid.
Spores within the cytoplasm of intestinal cells, Giemsa stain.

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E.bieneusi: H&E, Giemsa, Gram and Btol O are considered satisfactory
techniques for staining the intracellular spores of protozoa in tissue sections;
spores are usually in the supranuclear cytoplasm of the villous enterocytes.
(Giemsa stain).

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E.bieneusi: H&E, Giemsa, Gram and Btol O are considered satisfactory
techniques for staining the intracellular spores of protozoa in tissue sections;
spores are usually in the supranuclear cytoplasm of the villous enterocytes.
(Gram stain).

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E.bieneusi: transmission electron microscopy (TEM) is necessary
for species identification and for biological studies.
Proliferative plasmodial stage of E.b. with cytoplasm containing
ribosomes and a small amount of membrane.
Multiple elongated nuclei are adjacent to electronlucent inclusion.

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E.bieneusi, (T.E.M): early sporogonal stage marked by
electrondense disc formation.

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E.bieneusi, (T.E.M): sporogonial stage: the round dense nuclei are
associated with electrondense discs.

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E.bieneusi, (T.E.M): sporoblasts: electrondense discs fuse into arcs
forming polar tube coils. Sporoblast are irregulary shaped.

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E.bieneusi, (T.E.M): mature spores. Cross section shows seven coils
of the polar tube characteristic of E.bieneusi.

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Encephalitozoon intestinalis (formerly Septata intestinalis)
is associated with diarrhea, rhinosinusitis, nephritis and urethritis.
Spores are larger than spores of E.bieneusi and measure 2.5-3.3 by 1.3-2.1 µm.
(Weber mod. trichrome stain).

 
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