Monday, January 27, 2025

Case of the Week 768

This week's case was generously donated by Dr. Mike Mitchell. The following organism was found in the agar of a bacterial urine culture. It is about 1.5 mm in greatest dimension. Would you report this finding, and if so, how? 



6 comments:

Florida Fan said...

The organism has six legs and fits the morphology of insects. It resembles a so called “paper mite” though these do not exist. They are rather book lice, a threat to all mycology laboratories in particular for their cross contamination of cultures. The case may be true to bacterial cultures as well.
As such, their report in a clinical setting is contraindicated.

Idzi P. said...

Couldn't agree more with Florida Fan!
Definitely a book louse (psocid). Possibly Liposcelis spp. (Order Psocodea - suborder Troctomorpha - Family Liposcelididae).
Although these insects resembles lice, these critters are not true lice, not even parasites! They live in moist places and feed primarily on molds, fungi, starch, etc. They can be easily recognized by that funny weird "nose" (or "clypeus" in scientific terms) they have.
I'd suggest not to report this, as it concerns in incidental find or a contaminant. If found on a more regular basis, try to eliminate the source of contamination as quick as possible. The problem might be the storage of the agar plates in that case? Reducing RH below 50% and keeping it below that level should get rid of the psocids.

Anonymous said...

Wouldnt report it, accidental finding of book lice (?) but I would probably ask the doctor who is medically in charge of the lab./Patrik

Azra Hasan said...

It could be a Psocid (Booklice) but we can also have Collembola (Springtail) in the D/D

I looked up the difference from around and it seems like Springtails thrive in moist environments (e.g., soil, decaying organic matter, agar plates). They are common lab contaminants and feed on fungi/bacteria. On the other hand, Psocid (Booklice) prefer dry, starchy environments (e.g., books, stored grains) and are unlikely to colonize agar plates unless mold is present.

Anonymous said...

looks like an ant, maybe contamination; it is not for reporting.

Idzi P. said...

This critter's morphology is not consistent with that of Collembola's, so I'm pretty sure it's not a springtail. Springtails should have a typically curved tail in fact. I'll stick with my initial thought of Psocid. From what I've found, psocids do thrive in moist environments and can easiest be eliminated by reducing humidity in fact.