2022 Volume 71 Issue 1 Pages 53-60
Grocott’s methenamine silver staining is one of the commonly used methods in histological analysis and widely used to screen for fungal microorganisms. Some fungal species have small amounts of the hydroxy group in their cell walls; thus, the conventional protocol of Grocott’s staining, including the use of chromate for oxidation, sometimes gives weak staining. In addition, tissue sections after the antigen retrieval step, which is often used in immunohistochemical analysis, show weak staining of the connective tissue. In this letter, we report the results of our tests using several types of acid for oxidation and pretreatment in the original Grocott’s staining for the detection of Mucor spp. in sections as an example. Among the acids we tested, we found periodic acid to be the best oxidation agent for Mucor spp. This modification using periodic acid is useful for identifying Mucor spp. in tissue sections especially when a commercially available antibody to Rhizopus does not provide satisfactory staining.
