Gram staining
DefinitionThis section has been translated automatically.
Microbiological staining method for the detection of bacteria.
ImplementationThis section has been translated automatically.
- Fixation: Air-dry slides with bacteria (usually obtained from smear) and heat-fix (pass 3 times through the flame of a Bunsen burner!).
- Staining: Stain slides for 1-2 min in a staining chamber with carbolgentian violet (gentian violet 1.0 + ethanol 96% 10.0 + carbolic acid 5.0 + aqua dest. ad 100.0). Then carefully rinse the stain with cold tap water. Then rinse the slides with Lugol's solution (potassium iodate 2.0 together with iodine 1.0 in a little distilled water and make up to 300.0 ml with distilled water) and stain for 1-2 min in a staining chamber with Lugol's solution. Remove the slides and rinse with 96% ethanol until no more colour clouds come off.
- Re-staining: Stain slides for about 2 min. in a staining chamber with 10% carbol fuchsin solution. (fuchsin 1.0 + alcohol 96% 10.0 + carbolic acid 5.0 + distilled water ad 100.0). Then rinse with distilled water and air dry.
- Result: Gram-positive bacteria dark blue, Gram-negative bacteria red.