Comparison of Weber Green and Ryan Blue modified trichrome staining for the diagnosis of microsporidial spores from stool samples of HIV-positive patients with diarrhoea.

Microsporidia is increasingly being reported in the recent years in HIV-positive patients with diarrhoea.[1,2] Electron microscopy, though a gold standard for detection of microsporidial spores,[2] can only be used in sophisticated laboratories. Intestinal biopsy, though better, is not advocated in HIV-infected patients with diarrhoea because of its invasive nature.[3] therefore, trichrome staining still remains the most commonly used method for detection of microsporidial spores in routine laboratories. Therefore, on 30 stool samples of HIV-positive patients with diarrhoea, modiÞ ed trichrome staining, i.e., Chromotrope 2R staining, was performed in duplicate — one method using fast green (Weber Green method)[4] and the other method using aniline blue (Ryan Blue method).[5] The procedure of staining was similar for both. Smears were examined under oil immersion lens for pink-coloured spores 1 to 2 μm in diameter. Background appeared green in case of fast green and blue when aniline blue was used. Photographs of microsporidial spores by two staining methods are shown (Fig.).