Connie

Apologies if I am late to this thread and you have heard this already but I
recall an 80's short paper in Medical Laboratory Sciences which reported the
potential for false positive staining for AAFB after washing sections in tap
water contaminated with non-pathogenic varieties.  They recommended using
filtered wash water only.

Bill McMeekin
Senior Chief Biomedical Scientist
Neuropathology
Newcastle General Hospital
Phone: +44 191 256 3830
Fax: +44 191 256 3196
E-mail: bill.mcmeekin@nuth.northy.nhs.uk


-----Original Message-----
From: Connie McManus [mailto:conmac@cc.usu.edu]
Sent: 08 January 2002 19:19
To: Connie McManus; Noreen Gilman; histonet@pathology.swmed.edu
Subject: Re: A word on Acid Fast Bacteria


Folks,

a couple of you had very kindly pointed out to me an error in my memory...
Mycobacterium spp most certaoinly can reproduce outside of a living cell.
M. leprae being the exception to that.  All I can say is, it's been a long
time since I've done micro and at my ripe old age, memory fails.  Sorry
about that.  

I fail, however, to see how they can cause contamination in waterbaths,
staining solutions, or "jump" from control to case tissues.  I have never
had this experience nor heard of it until this thread.

Connie McManus

At 09:53 AM 1/7/02 -0700, Connie McManus wrote:
>
>This is primarily an FYI on acid fast bacteria.  
>Having worked as a microbiologist for almost 10 years, I know something
>about the bacteria that cause TB & leprosy (the acid fast organisms).  I do
>not believe ANY bacteria from a control tissue could ever contaminate a
>waterbath or another tissue section or a staining solution.  But
>Mycobacteria spp, (the acid fast bugs) are intracellular parasites, i.e.,
>they grow INSIDE the cells.   The property of being acid fast is a
>diagnostic feature of the genus Mycobacteria and all species in this genus
>are intracellular parasites.  They cannot reproduce outside of a living
>cell.  They may float around  in a moribund state, but that is not living
>and they most certainly cannot reproduce in such a condition.  To the best
>of my knowledge, there are not any acid fast bacteria that are associated
>with water.  Can some be found floating in water somewhere?  possibly, but
>I would be really concerned about how they got there.   There are plenty of
>gram negatives that are associated with water and the big slime producers
>in water containers are the Pseudomonads  and Flavomonas spp. (gram
>negatives) as well as some  yeasts.   Mycobacteria??  No.  Now, there may
>be other bacteria that are acid fast, but I cannot think of any other than
>Mycobacteria.  
>
>Just thought you might like to know...
>Connie McManus
>
>
>
>
>At 01:49 PM 1/3/02 -0500, Noreen Gilman wrote:
>>     I've got an unusual problem and I hope  you guys can help me.   I
have
>>never had a problem like this before. I'm at my wits  end. Any suggestion
>>are very welcome. Noreen   Noreen S. Gilman, HT (ASCP) CLS
>>Broward General Medical Center
>>Ft.  Lauderdale, FL 3316
>>954-355-5592 Phone
>>954-355-4139 Fax
>>ngilman@nbhd.org 
>
>Veterinary Diagnostics Lab
>Utah State University
>Logan, UT
>USA
>fax (435) 797-2805
>
>

Veterinary Diagnostics Lab
Utah State University
Logan, UT
USA
fax (435) 797-2805