A new trichrome-blue stain for detection of microsporidial species in urine, stool, and nasopharyngeal specimens

Abstract

Detection of microsporidia in clinical specimens has relied on electron microscopy, histology, or staining. This article describes further alterations to the modified trichrome staining method which make it easier to identify microsporidial spores. The changes are a decrease in the phosphotungstic acid level and the substitution of a colorfast counterstain, aniline blue, for the fast green of the original stain. The modified stain provides good contrast between microsporidial spores and background material including human and fungal cells. Stool specimens from 139 human immunodeficiency virus-seropositive patients revealed that 5 patients were infected with Enterocytozoon bieneusi and 6 patients had larger spores. Thin-section electron microscopy of the larger spores showed a structure consistent with that of either Encephalitozoon or Septata species. Three of the patients with Encephalitozoonor Septata-like species had disseminated infection, with spores detected in nasopharyngeal aspirates and urine samples.

Microsporidia (Encephalitozoon cuniculi) in wild rabbits in Australia

“…Giemsa and modified trichrome stains have been used to examine urine and faecal samples for microsporidia in humans. 5 However, because microsporidia are similar in size to bacteria, their detection is difficult and spores may be overlooked.…”

“…It was first described in 1922 as the cause of spontaneous paralysis in rabbits (Oryctolagus cuniculus) and subsequently observed in the brain of rabbits by Levaditi et al 3 Diagnosis of microsporidiosis in mammals was originally based on the identification of spores in histological sections. 2,4 Spores have also been detected in faeces and urine using a modified trichrome stain 5,6 or optical brightening agents such as Uvitex 2B. 7 The successful culture of E cuniculi spores in vitro has led to the development of several serological tests including indirect immunofluorescence, carbon immunoassay, complement fixation, immunoperoxidase and microagglutination tests.…”

Diagnosis of disseminated microsporidian Encephalitozoon hellem infection by PCR-Southern analysis and successful treatment with albendazole and fumagillin

“…For diagnostic purposes, however, transmission electron microscopy is time-consuming and relatively insensitive and requires a great deal of expertise. Histochemical methods using chitin-staining fluorochromes (11,31,(46)(47)(48)(49), modified trichrome staining (29,35,55), and IFA (1,38,58,63) were developed and compared for diagnosing microsporidia (16). A resulting diagnostics paradigm was to screen specimens with the calcofluor stain, because it is fast and easy to perform and read.…”

The First Report Ofintestinal Microsporidia From Wild Mammals in Egypt 1- Light Microscopy

“…The modified trichrome stain method was based on the fact that stain penetration of the microsporidial spore is very difficult; thus, the dye content in the chromotrope 2R component of the formula is greater than that used to prepare Wheatley's modification of the Gomori's trichrome stain, and the staining time is much longer (90 min) (Weber et al, 1992;Ryan et al, 1993).Stained smears were carefully examined using a light microscope with an oil immersion lens for the presence of microsporidian spores.…”