Tuesday, May 28, 2019

Case of the Week 546

This week's case has been generously donated by Blaine Mathison at ARUP. Two different types of objects were seen in a trichrome-stained stool specimen that was screened by a digital slide image and machine learning platform. How did it do? Did it find real parasites?

The following objects are approximately 8 to 13 micrometers in diameter:

These objects are 10 to 15 micrometers in greatest dimension.
Identification?

16 comments:

Anonymous said...

Top 2 - Blastocystis hominis, the others - Entamoeba coli

D. Otero

William Sears said...

blastocystis and entamoeba trophozoite. Can't describe ameoba further

Anonymous said...

Blastocystis and Entamoeba troph

Atiya kausar said...

Blastocystis hominis and trophozoite of Entamoeba coli

Lyne said...

Blastocystis hominis and Entamoeba sp.troph

Anonymous said...

Agree with others . . . but does this mean that our days as expert parasitology microscopists are numbered?

Anonymous said...

Blastocystis hominis and Entamoeba polecki

Anonymous said...

Yes, the first two pictures show typical Blastocystis spp. with peripheral chromatin lumps. We need to keep in mind that parasites are three dimensional and as such, I usually keep the liking of Blastocystis spp. to a clear plastic bag studded with lumps of chewing gum.
The two pictures of Entamoeba denote a vacuolated cytoplasm, large central chromatin and no chromatoidal rods or lumps, as such I would identify these as E. coli trophozoites.
Florida Fan

Sir Galahad said...


Blastocystis spp (fig. 1, 2); Entamoeba polechi, trofozoites ( fig. 3, 4, 5 e 6).

Marta MP said...

Blastocystis hominis and Entamoeba trophozoite

Sir Galahad said...
This comment has been removed by the author.
Idzi P. said...

Blastocystis for sure! But....
As I don’t have a lot of experience with trichrome staining, I would play it safe and say Entamoeba sp. for the second one...
Yet... the small overall size annoys me as well as the relative fine central karyosome and the rather fine peripheral chromatine. Therefore I would almost dare say: not E. coli, but rather E. histolytica/E. dispar (or E. polecki, nutalli, moshokvskii,...)

Old One said...

I agree with Idzi. The structure is like that of E. histolytica. The ectoplasm contains what appears to be bacterial inclusions(Photo lower left). However, the size range fits with that of E. histolytica small nonpathogenic race (12-15um) although my reference is a bit on the old side (Levine,1985) it probably has a new name by now.

The Blastocystis was an educational experience for me. Luckily I've been schooled by the very best.

I'm blowed away by this new fangled robot microscope. It didn't find parasites this time, but I believe it was because there were none in the sample. Blaine, can you make a living with your poetry?

Marc Couturier said...

Have no fear. We will all have jobs as expert parasitologists. This technology that Blaine and I have been working on will make our work MUCH easier, faster, and more accurate. And fun...because lets face it...no one likes sitting for 8 hours at a scope.
The future is bright for parasitology.

Anonymous said...

The size and central chromatin do agree with E. histolytica, but with the vacuolated cytoplasm these trophozoites seems compatible with E. coli.
Again the new technology gives us better methodology, in this case could it give us more details than necessary?
Florida Fan

Old One said...

Marc,

I hear you.

I haven't looked through a compound scope in 14 years. I do miss it, but I have suffered no ill effects. For the time being I will content myself with enjoying both your labs diagnostic and literary expertise.