The microscopic diagnosis of Pneumocystis carinii. An evaluation of the gram, the methylene blue, and the Ziehl-Neelsen procedures.

Abstract

An assessment of the Gram, the Methylene blue, and the Ziehl-Neelsen procedures in diagnosing Pneumocystis carinii has been performed. By using heat and methanol as fixatives and phase-contrast microscopy we found the procedures valuable in detecting the pneumocysts, especially in the Gram staining. The diagnosis should, however, be confirmed by a re-staining with a specific staining, viz. the toluidine blue 0 or the silver impregnation a.m. Gomori-Grocott. It is additionally shown that the staining a.m. Gomori-Grocott is dependent on the density of the preparation.