[Histonet] AFB

Lee & Peggy Wenk lpwenk <@t> sbcglobal.net
Sun Oct 17 21:02:23 CDT 2010

Hi - Can't find the original question - must have deleted it, so I'll answer 
through Cheryl's, if that's OK with her.

If I remember, the question was something like - are there other 
microorganisms besides TB that stain with Kinyoun (or something like that).

First, any mycobacterium (acid fast bacteria AFB) will stain with 
Ziehl-Neelsen, Kinyoun, Auramine-Rhodamine or Fites (hence anything staining 
with these stains is called AFB positive, meaning staining with these AF 
stains) . So that means Mycobacterium tuberculosis (TB), Mycobacterium avium 
intracellular (found in birds and I've seen it in spleen and bone marrow of 
immune suppressed patients), Mycobacterium paratuberculosis (found in 
intestine of infected cows and goats, causing something similar to Crone's 
disease), and a lot of other Mycobacterium are AFB positive staining with 
these procedures.

Mycobacterium leprae (leprosy) is a very thin walled mycobacterium, so needs 
the Fites stain with the peanut oil (or any other oil, such as mineral oil) 
to coat the leprosy microorganism, so it can withstand decolorization with 
aqueous alcohol. But Fites can also be used to demonstrate any of the 

These AFB stains will also demonstrate the sulfur clubs of actinomyces, and 
the filamentous strands of nocardia are also weakly AFB positive. (Sort of 
bacteria with some fungus characteristics.)

Cryptosporidium found in the intestine (causing severe diarrhea) can also 
stain AFB positive.

And there are bacterium (mycobacterium or others) in tap water that are AFB 
positive, which can adhere to your slides from the flotation bath water, or 
from the tap water.  Usually non-pathogenic AFB, but I don't know their 

And I'm sure there are other less common bacteria that I've forgotten or 
never known about that will stain AFB positive, which are not in the 
Mycobacterium genus.

And let's remember that hair follicles, sperm (heads with lipids), 
lipofucsin (wear and tear pigment of lipids) also stain AFB positive. And 
also Russell bodies (inclusions of antibodies in plasma cells) will stain 
AFB positive. And keratin which is dense can simply require longer 
differentiation, or else it will retain the red color of the dye.

So, yes, Amy, there are other things that stain positive with Kinyoun that 
are not TB/mycobacterium.

Peggy A. Wenk, HTL(ASCP)SLS
Beaumont Hospital
Royal Oak, MI 48073

From: "Cheryl Crowder" <ccrowder <@t> vetmed.lsu.edu>
Sent: Saturday, October 16, 2010 10:48 AM
To: <histonet <@t> lists.utsouthwestern.edu>
Subject: [Histonet] AFB

> Amy - The AFB (Ziehl-Neelsen, Kinyoun's, etc) will stain any acid-fast
> bacteria.  The Fite's stain is usually considered specific for 
> mycobacteria.
> Cheryl
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