An allochrome periodic acid-methenamine silver stain for demonstrating mycobacteria in tissue sections

Abstract

An allochrome periodic acid-methenamine silver stain is presented as being the most reliable and sensitive method for demonstrating myobacteria in tissues and its resultant pathology. The technic is as follows: deparaffinize formalin fixed sections, oxidize in 10% periodic acid for 24 hours, react methenanine silver at 60°C for 2 hours, after gold chloride, nuclear stain with nuclear fast red and counterstain in picro-methyl blue. Mycobacteria, elastic fibers and melanin are stained black in contrast with allochrome background and the chromophobic bacilli are demonstrated clearly.