This technique involves the argyrophilic reaction. The spirochetes are argyrophilic, which means they will absorb silver from a silver solution, but need a separate reducing agent in a solution to reduce the adsorbed silver to visible metallic silver. The stain demonstrates black spirochetes against a yellow to pale brown background.
- Acetate buffer, pH 3.6
- 1% silver nitrate solution in pH 3.6 acetate buffer
- Developer solution
sodium acetate = 4.1 gm
acetic acid = 6.25 gm
distilled water = 500 gm
2% silver nitrate = 15 ml
5% gelatin solution = 3.75 ml
15% hydroquinone = 12 ml
- Deparaffinize and bring sections to distilled water.
- Place slides in 1% silver nitrate solution for 45 seconds in microwave. Let stand for 1 minute at room temperature.
(Note: alternatively, in a laboratory microwave, heat at 80% power, 60ºC for 5 minutes, no standing time required).
- Prepare and preheat developer solution in water bath.
- Remove slides from silver solution. Do not rinse. Place slides horizontally on a slide rack and cover with developer. Allow sections to develop until they are light yellow to golden brown, approximately 1 minute or less.
- Wash quickly and thoroughly on hot tap water.
- Rinse in distilled water.
- Dehydrate, clear and mount.
Results and Interpretation
Spirochetes : black
Helicobacter pylori : black
Klebsiella : brown/black
Nuclei : brown
Background : golden yellow