RE: [Histonet] ZN stain

From:"Liz Chlipala"


I think that what you are describing does happen.  We handle quite a few
samples from TB research and there is some discussion that sometimes the
cell wall of the bacteria changes and is no longer acid fast.  We use
several methods here depending upon the project to look at TB in tissues
sections the most common one is the Ziehl-Neelsen stain, we have also tried
Wade-Fites modification for Leprosy, personally I did not see any
differences between the two stains in guinea pig tissues exposed to m TB.
We have also used a few IHC protocols, one being an anti-BCG antibody, but
you need to be careful with this one in working up the protocol we also
found that it also can stain gram positive bacteria, and it is not entirely
specific to m. tuberculosis, which I believe is stated right on the spec
sheet.  There are also some home grown antibodies that we have worked on
derived from culture supernates and some of those work also.  Because we are
working directly with the researchers on these projects we also have used
some really nice RNA probes that are specific to m. tuberculosis.

We have done extensive dual staining with anti-BCG, acid fast staining and
in-situ probes and there are instances in which they are all staining
different organisms.  I'm going to forward you in a different e-mail a few
papers and some contact information for a researcher up at Colorado State
University who we work with on occasion to run the probes on human tissue


Elizabeth A. Chlipala, BS, HTL(ASCP)QIHC
Premier Laboratory, LLC
P.O. Box 18592
Boulder, CO 80308
phone (303) 735-5001
fax (303) 735-3540
Ship to Address:
Premier Laboratory, LLC
University of Colorado at Boulder
MCDB, Room A3B40
Boulder, CO 80309

-----Original Message-----
[] On Behalf Of Michelle
Sent: Saturday, April 14, 2007 3:35 AM
Subject: [Histonet] ZN stain

Does anyone have a situation when staining for mycobacterium
tuberculosis with the ZN stain, get negative results in the tissue
sampled but the control is positive, in cases where the patient/deceased
is known to have had TB. I work with autopsy material and have this
situation when we know the person had TB but is negative in the test.
Anyone have any other stain to demonstrate TB bacilli or information on
this issue.

Many thanks

Forensic Pathology Services
Western Cape 
South Africa

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