Minty Tubes

in STEMGeeks2 months ago

         I don't think I have ever shown what Mycobacterium species look like on the LJ slants. No, the slants do not have a minty aroma. Some of the better-known bacteria from this genus include tuberculosis. Acid-fast bacillus (AFB) cultures are one of the tests with the longest incubation time we perform in microbiology. Per protocol, we cannot rule out their presence until 42 days have passed since inoculation.

         These are what M. tuberculosis looks like. They don't have picture-perfect colonies like the ones in the Wikipedia entry. They grew from a patient's sputum. So, nothing is out of the ordinary.

Textbook pic

         The stock photo reminds me of caviar. I hope I didn't ruin anyone's appetite.

         These are M. gordonae. They are usually flora found in the environment. Often, a patient is immunocompromised when they become infected by this species. These grew from a different patient's bronchial lavage.

         As far as I remember, we isolated multiple organisms from this patient. Aside from the Mycobacterium, there were also fungal infections and other bacterial agents. Needless to say, the patient was not doing well.

         Just for fun, each tube of LJ slant costs about $1. They usually come in boxes of 100. It's not the cheapest growth medium we use in the labs. Each month, we go through at least 600 cultures. I hope this gives you some perspective on the material costs of microbiology.

Posted with STEMGeeks


LJ slant here isn't the common route used to diagnosed. Either they get diagnosed by AFB sputum smear or clinically via x-ray because clinician can't wait for those 42 days. But LJ slants do get used on some institutions.

 2 months ago 

The trouble with direct smears is that if it's negative, you still can't rule out the possibility that it's there.

In the first picture, why does the third vial have a different minty color than the first two?

 2 months ago 

Different manufacturer. Continual supply chain constraints have left us with mix-and-matched products.


Going for that Victorian look? I hope Tuberculosis isn’t fashionable again.

 2 months ago 

Luckily, it’s not prevalent in the US.

The test tubes remind me of the ones we got in high school with fruit flies in them. They had the greenish blue stuff in them to help them grow. What is your take on this new deadly fungus that is circulating around?

 2 months ago 

We started testing for those for a year or so now.

Hard to kill, but really only a problem of you are immunocompromised.

As big of a deal as they are making it out to be? I figured you would be the guy to go to!

 2 months ago 

We only screen it for those type of patients.

Wao, this is so amazing. I remember doing some lab test like this in my college days, it was so amazing

 2 months ago 

These species have to be handled in a BSL-3 environment.

Yeah, I remember doing some that gave me some bad 😞 results until I had to do a retake of them all. Science is actually fun tho

600 cultures means, 600$ expense only on these tubes ?

 2 months ago 

Yup, that's just for the tubes. Not including wages and other stuff.

These slants aren't even the most expensive components used in these cultures. MGIT tubes are about $5 each and they are coupled with each LJ slant.

So, it's a very expensive business. are you guys are in profit or loss ?

 2 months ago 

Healthcare is a for-profit business in the US.

Glad to know that :) and wish you best of luck

Bang, I did it again... I just rehived your post!
Week 148 of my contest just can now check the winners of the previous week!

Nice slants! I'm just grateful I'm not the patient with that lovely culture... Thank goodness I never picked up TB in all my years of hospital care. Was exposed once but came back negative thank God. Thanks for sharing!

 2 months ago 

Glad you never got infected!

Me too! The treatment is very hepatotoxic and lots of side affects, yuck!

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