Survey Three 2001

Lung

Ziehl-Neelsen Method

A section of lung stained by Ziehl-Neelsen method. The lung is infected by Mycobacterium tubercule which would cause tuberculosis. This disease is not rare in Hong Kong but are highly controlled except some drug-resistant bacilli are found.


Higher magnification shows some stained tubercle bacilli (TB). Their lipid capsules cause problem for the stain to penetrate into the organisms. However once the bacteria are stained, it is resistant to removal by acid and alcohol. Therefore the Ziehl-Neelsen technique uses heat to force carbol fuchsin into the bacteria and then removes the stain from other structures, except red cells and TB, with acid alcohol.


Attention should be paid to avoid fire hazard when using naked flame for steaming the staining solution. Prolong staining at room temperature can also give good results. The best performer of this survey used 20 minutes. Other points are: (1) positive control sections should ALWAYS be used, (2) the acidified methylene blue counterstain should be pale to facilitate detection of the red-staining organisms.


Last updated on 22 December, 2001.

Prepared by HKIMLSQAP Anatomical Pathology Panel.

Copyright 2001 HKIMLSQAP. All Rights Reserved.