A technician has just performed a Gram stain but forgot to add the safranin. What is the likely result of this stain when viewed microscopically?

A technician has just performed a Gram stain but forgot to add the safranin. What is the likely result of this stain when viewed microscopically?

• A. Gram-positive organisms will appear red
• B. All organisms will appear blue
• C. Gram-negative organisms cannot be seen under the microscope
• D. Only Gram-positive organisms will be visible

Answer: (C)

When the Gram stain procedure is performed without the addition of safranin, the final result will lead to a misunderstanding of what can be visualized under the microscope. The Gram stain involves using crystal violet dye, which stains all bacteria initially. Following this, iodine is applied to form a crystal violet-iodine complex, which can be retained by Gram-positive bacteria but not by Gram-negative bacteria in the subsequent steps.

Safranin serves as a counterstain, providing a color to Gram-negative bacteria that do not retain the crystal violet after the decolorization step with alcohol or acetone. If safranin is omitted, the Gram-negative organisms will not take up any counterstain and thus will not contribute any color, making them virtually invisible against the background. Since Gram-positive bacteria will retain the crystal violet and appear blue, only Gram-positive organisms will be visible under the microscope without the counterstain. Therefore, it's crucial to understand that without the safranin, Gram-negative bacteria can't be differentiated and will not be detectable; they will not contribute to the viewing results. Thus, the result from the Gram stain under these circumstances will prominently show only the Gram-positive organisms, making the distinction clear.