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Acid fast bacilli isolated, but no identification?

Posted by dltorres @dltorres, Jul 10, 2023

Hi, I have a sputum sample that was submitted 4 months ago. My doctors office called to get results & was told this;
*AFB: smear negative for acid fast bacilli.
*Culture: Acid fast bacilli isolated. Identification to follow.
I was wondering if anyone else had such a long wait & what was finally identified?
Thanks!

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Sue, Volunteer Mentor | @sueinmn | Jul 14, 2023

@dltorres I have not heard of it taking so long, and I am not a bacteriologist, but it sounds like a lab that needs to follow up.
Here is what usually happens to a sputum sample when NTM is suspected - First, a small amount is placed on a slide and inspected under a microscope to determine what bacteria is there. When NTM or Pseudomonas is suspected, the tech is looking for bacilli with a specific resistance to a tiny amount of acid and with specific shapes. If any are seen on the slide, they are described.

Then, a larger amount of the sample is smeared on growth medium in a specimen dish, placed in an incubator and we wait. Often this is done in a specialized lab, with techs experienced in identifying rare bacteria. It is checked periodically during a growth period of 4 to 8 weeks. If the specimen grows, highly trained techs identify the specific strain of bacteria growing, and begin applying antibiotics to the growing bacteria to see what kills it. The longest it ever took for my specimens was 7 weeks.

Now the question is what to do next. It sounds to me like your culture may not have gone to a specialized lab with a set protocol, and thus has "fallen through the cracks." Perhaps you and your doctor should consider doing another specimen, and this time be sure it gets to a specialized lab? Or perhaps it is time to see a pulmonologist or ID doc experienced in treating NTM?

What has the doctor suggested?
Sue

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1 reply
dltorres | @dltorres | Jul 14, 2023
In reply to @sueinmn "@dltorres I have not heard of it taking so long, and I am not a bacteriologist,..." + (show)
@sueinmn

@dltorres I have not heard of it taking so long, and I am not a bacteriologist, but it sounds like a lab that needs to follow up.
Here is what usually happens to a sputum sample when NTM is suspected - First, a small amount is placed on a slide and inspected under a microscope to determine what bacteria is there. When NTM or Pseudomonas is suspected, the tech is looking for bacilli with a specific resistance to a tiny amount of acid and with specific shapes. If any are seen on the slide, they are described.

Then, a larger amount of the sample is smeared on growth medium in a specimen dish, placed in an incubator and we wait. Often this is done in a specialized lab, with techs experienced in identifying rare bacteria. It is checked periodically during a growth period of 4 to 8 weeks. If the specimen grows, highly trained techs identify the specific strain of bacteria growing, and begin applying antibiotics to the growing bacteria to see what kills it. The longest it ever took for my specimens was 7 weeks.

Now the question is what to do next. It sounds to me like your culture may not have gone to a specialized lab with a set protocol, and thus has "fallen through the cracks." Perhaps you and your doctor should consider doing another specimen, and this time be sure it gets to a specialized lab? Or perhaps it is time to see a pulmonologist or ID doc experienced in treating NTM?

What has the doctor suggested?
Sue

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Hi Sue, Just got the results: Mycobacterium lentiflavum. I found info that you wrote about M. Lentiflavum & posted a question this morning on that thread.
Thanks so much for the info & have a great day!
Debra

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