How to Prepare a Microbiology Smear

Staining is the main way in which organisms can be scientifically observed and classified under a microscope. To properly prepare a slide for staining in a microbiology laboratory, follow the easy steps below.

Things You'll Need

• Glass microscope slide
• Coverslip
• Pasteur pipette
• Bunsen burner and gas supply, or alcohol lamp
• Bacterial fluid

Instructions

1. Using a pipette, apply the bacterial fluid (which contains the bacteria you would like to observe) to a clean glass slide.

2. Smear the fluid evenly across the surface of the microscope slide with the edge of a coverslip.

3. Turn on the Bunsen burner or alcohol lamp. Holding the slide with a pair of forceps, pass it through the open flame two or three times. This fixes the cells to the microscope slide.

4. At this point, the cells are ready to be stained with whatever color stain you would like to apply.

Tips & Warnings

• If you don't have the bacteria in a liquid suspension, you can directly sample the bacterial area with an applicator stick and smear it across the surface of the slide. This method is useful when taking mouth cultures, for example.

• Be careful with any open flame. Watch loose objects, clothing and hair when operating your Bunsen burner.

• Always wear gloves when working with bacteria in a laboratory.