- Ziehl-Neelsen stain
The Ziehl-Neelsen stain, also known as the acid-fast stain, was first described by two German doctors;
Franz Ziehl(1859 to 1926), a bacteriologist and Friedrich Neelsen(1854 to 1894), a pathologist. It is a special bacteriological stain used to identify acid-fastorganisms, mainly Mycobacteria. " Mycobacterium tuberculosis" is the most important of this group, as it is responsible for the disease called tuberculosis(TB). It is helpful in diagnosing Mycobacterium tuberculosis since it's lipid rich cell wall makes it resistant to Gram stain. It can also be used to stain few other bacteria like " Nocardia". The reagents used are Ziehl-Neelsen carbolfuchsin, acid alcohol and methylene blue.
* 1. Cover with tissue paper
* 2. Flood slide with
carbolfuchsin, the primary stain, for 2 minutes while heating with steam.
* 3. Remove paper cover, decolorize slide with a mixture of
hydrochloric acidand ethanol.
* 4. Counter stain with
* 5% Sulphuric Acid is used for staining "Mycobacterium leprae" instead of the 20% used for "Mycobacterium tuberculosis"
Kinyounmodification (or cold Ziehl-Neelsen technique) is also available.
* "Microbiology with Diseases by Body System", Robert W. Bauman, 2009, Pearson Education, Inc.
Online protocol examples
* [http://www-medlib.med.utah.edu/WebPath/HISTHTML/MANUALS/AFB.PDF Ziehl-Neelsen] protocol (PDF format).
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