We are examining tissue from a cluster of human and canine patients with a similar pattern of systemic illness of unknown cause. All members of the cluster have evidence of motile zoospore-like objects in their blood and other tissue aspirates. Control wet-mount preps from healthy relatives of these patients do not show the presence of such motile objects.
Despite the tiny size of these motile objects, the “swimming” motion seems more consistent with the “falling leaf” forward motility pattern associated with a eukaryotic flagella than with bacterial motility patterns. Also, the staining patterns and SEM appearance of these objects appears more consistent with a eukaryote.
Preliminary sequencing studies have suggested sequence homology with stramnopile-type organisms. We are attempting to sequence cultured colonies of the organism but are having extremely low DNA yields despite robust growth of the organism in culture.
We would appreciate the opinion of those familiar with the morphology and zoospore motility of oomycete and related type organisms about the similarities and differences seen in these movies of motility in unstained, aseptically collected adipose tissue nodules from a patient in this cluster, suspected to be infected with a novel or emerging type of eukaryotic pathogen.
@Phil Geis:
Thanks for the reply. Yes, we have been able to grow it in culture reliably, however, it has unusual behavior in culture (as compared with common bacteria or fungi). The growth in culture is fast (colonies apparent in 24-36 hr). But, the classic appearance of the colonies is subtle as they appear to be transparent (visible as a clearing in opaque culture media or blood agar), and the bulk of the growth is within the culture medium rather than on the surface.
The colonies will quickly spread through the entirety of the agar culture medium, but it can be very difficult to see grossly, and we have had to rely on using sterile technique to cut out a block of agar dostant from the innoculation site and examine a stained piece of this block for presence of motile spores to confirm that the growth had spread to this extent. We also do sometimes get growth of surface colonies. These are waxy and pale yellow in color. They tend to appear about 1cm away from the innoculation site and contain toghtly packed objects that casually resemble cocci, but close inspection shows that they are not perfectly spherical, and, they will develop into hyphal (pseudohyphal?) like shapes upon addition of sterile water.
I csnt seem to add photos to my replies, but if you are interested, id be happy to e-mail you photos of the colony appearance and cytology appearance.
PS- sorry for typing errors, im on the mobile app version of researchgate and i cant see the textbox where i am typing for some reason.
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