A NEW TRICHROME-BLUE STAIN FOR DETECTION OF MICROSPORIDIAL SPECIES INURINE, STOOL, AND NASOPHARYNGEAL SPECIMENS

Detection of microsporidia in clinical specimens has relied on electro n microscopy, histology, or staining. This article describes further a lterations to the modified trichrome staining method which make it eas ier to identity microsporidial spores. The changes are a decrease in t he phosphotungstic acid level and the substitution of a colorfast coun terstain, aniline blue, for the fast green of the original stain. The modified stain provides good contrast between microsporidial spores an d background material including human and fungal cells. Stool specimen s from 139 human immunodeficiency vims-seropositive patients revealed that 5 patients were infected with Enterocytozoon bieneusi and 6 patie nts had larger spores. Thin-section electron microscopy of the larger spores showed a structure consistent with that of either Encephalitozo on or Septata species. Three of the patients with Encephalitozoon- or Septata-like species had disseminated infection, with spores detected in nasopharyngeal aspirates and urine samples.