Monday, May 2, 2022

Case of the Week 680

 This week's case is from Drs. Harsha Sheorey and Lauren McShane from Australia. The following were seen in bronchial washings from an immunocompromised patient (fluorescent prep for fungi and wet preps):

Here are the culture plates from the bronchial washings.

The patient also has Gram negative bacteremia. 

Diagnosis? As a bonus, what forms are we seeing in the respiratory specimens?


Anonymous said...

Strongyloides larva

Anonymous said...

Hookworm infection. Larvae

Anonymous said...

From the photographs, I can see a short buccal cavity, the genital primordium and the notched tail. All point to a mix of rhabditiform as well as filariform larvae of S. stercoralis.
Florida Fan

Anonymous said...

The overall clinical picture suggests disseminated strongyloidiasis to me. The blood culture plates (especially the first one) also seem to show, as the worm moves through the agar, it drags bacteria with it and they form tiny colonies in its path. The bacteraemia might be a result of helminth migration from the GI tract into the body and taking the bacteria with it, or bacteraemia from a separate infection given the immunocompromise.

Ben B said...

I think you would only see the L3 form in a bronch wash. As I remember the L1 remains in the GI lumen to be shed in the stool. As opposed to other nematodes, eggs will be exceedingly rare from stool for S. stercoralis.

I suppose if you did see L1 larvae from the clinical sample you could rule out hookworm since the eggs need to embryonate in the environment prior to hatching... My understanding is that the morphologic differentiation b/w hookwork and strongy is mostly useful if you are doing culture as it is a situation in which L1 forms of either could be present.

PCoyne said...

S. stercoralis, L3 stage.
Never heard of hookworm doing this.
And the plates are blood agar, not 'blood culture' plates, correct?

ParasiteGal said...

Great catch PCoyne! They are blood agar plates for culturing the bronch washing specimens. I updated the text to agar plates for simplicity.

Anonymous said...

Where do you find L2 larvae, I thought they could be found in respiratory specimen ?