Staining solutions: Gram stain kit

The stains used in Bacteriology are used to help the morphological visualization of bacteria, which due to their insignificant size are practically transparent.

Differential methods make it possible to distinguish bacteria belonging to different staining groups.

The Gram method differentiates bacteria into two large groups according to the color they acquire with the staining, purple for gram positives and pink for gram negatives. This property is conditioned by the different composition of the cell wall of both groups. It is advisable to carry out the staining from young cultures (24-36 h).