What is the first step in performing a Gram Stain?

The first step in performing a Gram stain is indeed fixing the sample, which is typically done using methanol. This process is crucial as it adheres the bacterial cells to the glass slide and prevents them from being washed away during the staining procedure. Fixation also preserves the morphology of the cells, allowing for accurate observation under the microscope.

In the context of Gram staining, subsequent steps involve adding specific reagents such as crystal violet, which stains all bacteria, followed by iodine, which forms a complex with the crystal violet that helps to trap the dye within Gram-positive bacteria. Then, a decolorizer is applied, which differentiates between Gram-positive and Gram-negative bacteria. Finally, safranin is used as a counterstain to enable visualization of Gram-negative bacteria. Thus, initiating the process with fixation is critical to ensure the reliability of the test results.