Atlante dei protozoi intestinali umani, identificazione microscopica di Giovanni Swierczynski e Bruno Milanesi

Fig. 1. Entamoeba coli. Wet mount examination of unfixed specimen. Trophozoite with hyaline pseudopod and cytoplasm containing numerous vacuoles. In unfixed specimens, the nucleus is not always seen.

Fig. 2. Entamoeba coli. Giemsa's stain. Same specimen as in Fig. 1. Trophozoite with nucleus stained red-violet and cytoplasm filled with coarse granules and vacuoles.

Fig. 3. Entamoeba coli. Wet mount examination of unfixed specimen. Rounded trophozoite (pre-cystic stage): the nucleus is not visible.

Fig. 4. Entamoeba coli. Giemsa's stain. Same specimen as in Fig. 3. Rounded trophozoite (pre-cystic stage) with a red-violet-stained nucleus and light-blue-stained cytoplasm containing vacuoles and abundant fecal debris.

Fig. 5. Entamoeba coli. Wet mount examination of formalin-fixed specimen. Right, a trophozoite with hyaline ectoplasm (arrow) clearly distinct from the coarsely granular endoplasm containing numerous vacuoles; the nucleus is seen but it is usually not sufficiently distinctive for species identification. Left, only five nuclei are seen in this mature cyst. In formalin-fixed specimens, amoebic cysts (but not trophozoites) can be identified from the distinctive appearance of the nuclei.

Fig. 6. Entamoeba coli. Giemsa’s stain. Center, a trophozoite fixed during movement: two pseudopods are seen; the cytoplasm is vacuolated and granular. Lower right, a mature cyst: only five nuclei are visible.

Fig. 7. Entamoeba coli. Wet mount examination. Left, a formalin-fixed trophozoite: the features of the nucleus are not clear. Right, a SAF-fixed trophozoite: with SAF fixative, this species' distinctive nuclear features (e.g. a large, non-compact, usually eccentrically located karyosome; peripheral chromatin characteristically in the form of coarse granules of irregular size distributed along the nuclear membrane) are clearly seen.

Fig. 8. Mixed infection. Wet mount examination of SAF-fixed specimen. Left, a Trichuris trichiura egg. Right, an Entamoeba coli trophozoite.

Fig. 9. Entamoeba coli. Iodine stain of SAF-fixed specimen. Two trophozoites. In the left one, fixed during movement, a pseudopod is clearly seen. In both, inside the cytoplasm are seen numerous food vacuoles containing various inclusions and typically it is characterized as being “dirty”.

Fig. 10. Entamoeba coli. Iodine stain of SAF-fixed specimen. The nucleus of this trophozoite has a large, diffuse karyosome. Occasionally the peripheral chromatin may appear as a regular dark ring.

Fig. 11. Entamoeba coli. Wet mount examination of SAF-fixed specimen. A trophozoite with a large ingested starch granule.

Fig. 12. Entamoeba coli. Iodine stain of SAF-fixed specimen. Two trophozoites with large ingested starch granules. The right one has also phagocytized a Giardia intestinalis cyst (arrow).

Fig. 13. Entamoeba coli. MIF stain. A trophozoite with a lightly egg-shaped nucleus and eccentrically located karyosome.

Fig. 14. Entamoeba coli. Bailenger’s stain. Two trophozoites of different shapes. In both, the distinctive features of the nucleus of this species are clearly seen.

Fig. 15. Entamoeba coli. Bailenger’s stain. A trophozoite parasitized by Sphaerita sp.

Fig. 16. Entamoeba coli. Iron hematoxylin stain. Well-stained vegetative form: the cytoplasm contains abundant fecal debris.

Fig. 17. Entamoeba coli. Iron hematoxylin stain. Telophase of a vegetative form: the nuclei are well separated.

Fig. 18. Entamoeba coli. Mayer’s hematoxylin. Two dividing trophozoites. The right one is at the beginning of cytodieresis.

Fig. 19. Entamoeba coli. Iron hematoxylin stain. These three vegetative forms have characteristic nuclei with large, non compact karyosomes eccentrically located and thick, uneven peripheral chromatin. The cytoplasm in each of these organisms is vacuolated and contains ingested starch granules, bacteria and other fecal debris.

Fig. 20. Entamoeba coli. Mayer’s hematoxylin. An elongated trophozoite.

Fig. 21. Entamoeba coli. Iron hematoxylin stain. A curious appearance of a trophozoite inside a loose vegetable spiral.

Fig. 22. Entamoeba coli. Iron hematoxylin stain. A Giardia intestinalis cyst phagocytized by a trophozoite whose nucleus is seen near the cytoplasmic membrane (arrow).

Fig. 23. Mixed infection. An Entamoeba coli trophozoite and two Chilomastix mesnili trophozoites (arrows).

Fig. 24. Entamoeba coli. Trichrome stain. Unusual shape of a vegetative form with fragmented karyosome. Inside the cytoplasm, some starch granules are seen.

Fig. 25. Entamoeba coli. Trichrome stain. Trophozoite with eccentrically located, diffuse karyosome and achromatic granules (chromosomes).

Fig. 26. Entamoeba coli. Trichrome stain. Trophozoite with large, diffuse, eccentrically located karyosome. The chromatin granules (nucleoli) are clearly seen on the nuclear membrane.

Fig. 27. Entamoeba coli. Trichrome stain. Note the strongly vacuolated cytoplasm of this trophozoite.

Fig. 28. Entamoeba coli. Trichrome stain. Vegetative form parasitized by two Sphaerita.

Fig. 29. Entamoeba coli . Trichrome stain. Center, a vegetative form with two dividing nuclei (telophase). Lower right, a mononucleate vegetative form: the karyosome is eccentrically located and two achromatic granules (chromosomes) are seen.

Fig. 30.Entamoeba coli. Trichrome stain. The nuclei of these two trophozoites are in anaphase.

Fig. 31. Mixed infection. Trichrome stain. Above, an Entamoeba coli trophozoite. Below, an Endolimax nana trophozoite. Besides the sizes, note the different appearances of the two nuclei.

Fig. 32. Entamoeba coli. Saline smear. Even in an unfixed specimen, it is possible to see several nuclei in each of these four cysts.

Fig. 33. Entamoeba coli. Iodine stain. Immature binucleate cyst with large iodophilic vacuole. Often, in binucleate cysts of this species, the nuclei are in opposite positions with respect to the vacuole, whereas in Entamoeba histolytica/dispar cysts the nuclei are paired.

Fig. 34. Entamoeba coli. Giemsa’s stain. An immature binucleate cyst.

Fig. 35. Entamoeba coli. Wet mount examination. Left, five nuclei are seen in this immature cyst: three are large whereas two, arising from a recent nuclear division, are small. Right, this tetranucleate cyst must not be mistaken for a mature cyst of Entamoeba histolytica/dispar: the two larger nuclei show that nuclear division is not yet finished.

Fig. 36. Entamoeba coli. Wet mount examination. Left, two cysts: only two dividing nuclei are in focus. Right, a cyst with two nuclei in the focal plane whereas a dividing nucleus (arrow) is barely visible.

Fig. 37. Entamoeba coli. Iodine stain. Left and right, two cysts with dividing nuclei.

Fig. 38. Entamoeba coli. Wet mount examination. Two cysts with chromatoid bodies that are splinter-like with pointed ends.

Fig. 39. Entamoeba coli. Iodine stain. A cyst with eight nuclei (mature) and chromatoid bodies which are seen less frequently in these cysts than in Entamoeba histolytica/dispar cysts.

Fig. 40. Entamoeba coli. Iodine stain. Note how readily apparent the nuclei are in the three cysts (left), despite the use of a lower magnification than that used to view the cyst on the right.

Fig. 41. Entamoeba coli. Iodine stain. Left and right, not all the nuclei are thoroughly in focus in these mature cysts.

Fig. 42. Entamoeba coli. Giemsa’s stain. Left and right, appearance of two mature cysts with this staining method.

Fig. 43. Entamoeba coli. Wet mount examination. Note the variable shapes that cysts of this species can assume.

Fig. 44. Entamoeba coli. Iodine stain. A mature, pear-shaped cyst.

Fig. 45. Entamoeba coli. Two supernucleate cysts with 16 nuclei. Left, unstained cyst. Right, iodine-stained cyst.

Fig. 46. Mixed infection. Iodine stain. Compare the size of the immature, smaller Entamoeba hartmanni binucleate cyst (arrow) with that of the much larger Entamoeba coli cyst (arrowhead).

Fig. 47. Entamoeba coli. MIF stain. A mature cyst: only five nuclei are visible.

Fig. 48. Entamoeba coli. Bailenger’s stain. An irregular-shaped immature cyst. Inside, two nuclei are clearly seen whereas the other two are barely visible. Note the unstained glycogen vacuole.

Fig. 49. Entamoeba coli. Bailenger’s stain. A mature cyst.

Fig. 50. Entamoeba coli. Bailenger’s stain. Only one nucleus is clearly visible in this cyst that contains a chromatoid body with pointed ends.

Fig. 51. Entamoeba coli. Trichrome stain. Left, the mononucleate cyst has a large, central glycogen vacuole. Inside the nucleus, the large karyosome displays intense karyokinetic activity. At the periphery of the cyst, there are numerous chromatoid bodies. Right, a mononucleate cyst in which the nucleus partially obscures the glycogen vacuole.

Fig. 52. Entamoeba coli. Left, iron hematoxylin stain. Right, trichrome stain. Two mononucleate cysts: the large, central glycogen vacuoles have compressed the nuclei to the margin of the cysts.

Fig. 53. Entamoeba coli. Trichrome stain. A binucleate cyst with two slightly elliptical nuclei in a phase of division.

Fig. 54. Entamoeba coli. Trichrome stain. Left and right, two binucleate cysts with nuclei that are at opposite sides with respect to the vacuole. This appearance distinguishes Entamoeba coli from Entamoeba histolytica/dispar cysts.

Fig. 55. Entamoeba coli. Mayer’s hematoxylin. Left and right, two mature cysts. Mature Entamoeba coli cysts tend to be more refractile when they are fixed and they may collapse during the staining procedure. This is not due to the fixative or the stain, but rather to a characteristic of this species.

Fig. 56.Entamoeba coli. Trichrome stain. Left and right, two mature cysts with five nuclei visible.

Fig. 57. Entamoeba coli. Trichrome stain. A mature cyst with eight nuclei.