Intestinal protozoa: Difference between revisions
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* Some have classic appearance: |
* Some have classic appearance: |
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** ''[[Giardia]]'' trophs look like an owl |
** ''[[Giardia]]'' trophs look like an owl |
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* ''[[Balantidium coli]]'' is huge |
** ''[[Balantidium coli]]'' is huge |
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** ''[[Trichomonas]]'' and ''[[Chilomastix]]'' trophs have flagellae and are tear-drop shaped |
** ''[[Trichomonas]]'' and ''[[Chilomastix]]'' trophs have flagellae and are tear-drop shaped |
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* ''[[ |
** ''[[Cystoisospora belli]]'' looks like an eye or halved egg |
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** ''[[Cyclospora]]'' is thick-walled and looks like a golf ball |
** ''[[Cyclospora]]'' is thick-walled and looks like a golf ball |
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* ''[[Cryptosporidium]]'' is the smallest (4-6 µm) and may have crescent-shaped sporozoites inside |
** ''[[Cryptosporidium]]'' is the smallest (4-6 µm) and may have crescent-shaped sporozoites inside |
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** ''[[Sarcocystis]]'' is quite large (15 µm), non-acid-fast, and looks like 2 joined ovals |
** ''[[Sarcocystis]]'' is quite large (15 µm), non-acid-fast, and looks like 2 joined ovals |
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* In order to differentiate the larger Amoebae, need to consider the size, nucleus characteristics, and other features |
* In order to differentiate the larger Amoebae, need to consider the size, nucleus characteristics, and other features |
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** Does is stain acid-fast? If yes, it is one of the sporas |
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* What kind of nucleus is it? |
** What kind of nucleus is it? |
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** Entamoeba: dark ing of peripheral chromatin, with a defined central nucleus and relatively clear perikarysomal space |
*** Entamoeba: dark ing of peripheral chromatin, with a defined central nucleus and relatively clear perikarysomal space |
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** Non-entamoeba: more blob-like, less well defined |
*** Non-entamoeba: more blob-like, less well defined |
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** Granulated: big dots, suggests ''[[Dientamoeba fragilis]]'' trophozoite |
*** Granulated: big dots, suggests ''[[Dientamoeba fragilis]]'' trophozoite |
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* How many nuclei? |
** How many nuclei? |
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** Trophs are mostly mono-nucleated, cysts may be poly-nucleated |
*** Trophs are mostly mono-nucleated, cysts may be poly-nucleated |
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** ''[[Dientamoeba]]'' has 2 nuclei in troph form |
*** ''[[Dientamoeba]]'' has 2 nuclei in troph form |
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* What is the average size? |
** What is the average size? |
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** Need a measurement microscope |
*** Need a measurement microscope |
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* Other stuff |
* Other stuff |
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** Large vacuole suggests ''Iodamoeba butschlii'' |
** Large vacuole suggests ''Iodamoeba butschlii'' |
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Revision as of 14:12, 10 October 2019
Microbiology
- Protozoans are eukaryotic unicellular organisms that have organelles
- Many have a trophozoite form (active, motile), as well as a cyst form (vegetative)
- Stains:
- Iron hematoxilin, which stains nuclei on a black background
- Acid-fast stain, which highlights red Crypto/Cyclo/Iso
- Can combine both of the above
Classification
From largest to smallest family
- Amoebae
- Entamoeba histolytica/dispar (microscopically indistinguishable, but E. dispar is non-pathogenic)
- Entamoeba harmanni and Entamoeba coli (non-pathogenic)
- Endolimax nana
- Iodamoeba butchlii
- Flagellates
- Giardia lamblia
- Dientamoeba fragilis (no cystic form)
- Chilomastix mesnili
- Ciliates
- Coccidia: small, may be seen as acid-fast
- Cryptosporidium species
- Cyclospora cayetanensis
- Cystoisospora belli (previously called Isospora)
- Sarcocystis hominis
- Microsporidia
Approach to Microscopy
- Some have classic appearance:
- Giardia trophs look like an owl
- Balantidium coli is huge
- Trichomonas and Chilomastix trophs have flagellae and are tear-drop shaped
- Cystoisospora belli looks like an eye or halved egg
- Cyclospora is thick-walled and looks like a golf ball
- Cryptosporidium is the smallest (4-6 µm) and may have crescent-shaped sporozoites inside
- Sarcocystis is quite large (15 µm), non-acid-fast, and looks like 2 joined ovals
- In order to differentiate the larger Amoebae, need to consider the size, nucleus characteristics, and other features
- Does is stain acid-fast? If yes, it is one of the sporas
- What kind of nucleus is it?
- Entamoeba: dark ing of peripheral chromatin, with a defined central nucleus and relatively clear perikarysomal space
- Non-entamoeba: more blob-like, less well defined
- Granulated: big dots, suggests Dientamoeba fragilis trophozoite
- How many nuclei?
- Trophs are mostly mono-nucleated, cysts may be poly-nucleated
- Dientamoeba has 2 nuclei in troph form
- What is the average size?
- Need a measurement microscope
- Other stuff
- Large vacuole suggests Iodamoeba butschlii
- Uneven chromatin suggests E. coli
- Chromatoidal bars suggests E. polecki, E. histolytica, or E. hartmanni
| Organism | Nucleus type | No. nuclei | Size | Other features |
|---|---|---|---|---|
| E. histolytica | Entamoeba type | 2-4 | > 10 µm | Chromatoidal bars |
| E. coli | Entamoeba type | 5-8+ | > 10 µm | |
| E. hartmanni | Entamoeba type | < 10 µm | Chromatoidal bars | |
| E. polecki | Entamoeba type but 1/3 cell width | > 10 µm | Chromatoidal bars, but may have glycogen mass | |
| Iodamoeba | Blob-like | 1 | Large vacuole | |
| Endolimax | Blob-like | 2-4 |
