|Description:||Under a magnification of 500X, this micrograph of a biopsied lung tissue specimen was stained using the Center for Disease Control's modified Dieterle silver impregnation procedure, revealing small, blunt, pleomorphic intracellular, and extracellular bacilli, which stain brown to black against a yellow background; Mag. 500x.|
Dieterle’s stain is a preparation used when Legionella pneumophila bacteria are suspected. Uranyl nitrate is applied in order to first sensitize the slide mount, which is subsequently treated with gum mastic, followed by an incubation period, after which the slide is soaked in silver nitrate. Lastly, the slide is “developed” in a hydroquinone, sodium sulfite, acetone, formaldehyde, pyridine, and gum mastic bath. The Legionella pneumophila bacteria, if present, will stain black.