Evaluation of Alcian Blue 8GS and Pyronin B Stain for Rapid Wet Mount Preparation of SAF Preserved Specimen Containing Entamoeba histolytica and Giardia intestinalis

Abstract

The microscopic examination of saline-diluted and iodine-stained wet mount preparations has satisfactorily been adopted in many laboratories as a simple and definite diagnostic measure. But, it is known that some difficulties have sometimes taken place in detection and identification of protozoa with this examination. We examined the usefulness of SAF (sodium acetate, acetic acid, and formalin) fixation, and alcian blue 8GS and pyronin B (AP) stain for wet mount preparations of fecal materials taken from amoebiasis and giardiasis patients in this study. SAF fixation was found very effective for preserving the morphological characters of protozoa, especially the inner structure, and for giving the good stainability to AP stain. The protozoa stained with AP, either trophozoites or cysts, showed the clear contour distinguishable from outer admixtures with the nuclear membrane and the karyosome stained deep purple, and the chromatoid body colored deep red. This was confirmed by the fact that the protozoa were not stained well with AP when not fixed with SAF. This method would be usable for the routine examination of fecal materials in intestinal protozoan infections, particularly Entamoeba histolytica and Giardia intestinalis infections. SAF fixative could also be used as a long-term preservative of protozoa in fecal materials.