How to Stain Smears of Staphylococcus Under a Light Microscope

While many species of the Gram-positive bacteria staphylococcus exist harmlessly on the skin, some species cause disease if allowed to enter the body through a cut or scrape. To confirm the presence of staphylococcus a lab technician affixes a smear of the bacteria to a slide, stains it and views it under a light microscope. Staining the smear makes it easier to identify staphylococcus.

Things You'll Need

• Slide with staphylococcus smear
• Forceps
• Bunsen burner
• Gloves
• Staining rack
• Stain
• Side drying rack
• Distilled water in wash bottle
• Blotting paper

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Instructions

• 1

  A Bunsen burner heats the slide to fix the smear.

  Hold the slide with the forceps and pass the bottom of the slide across the tip of the Bunsen burner flame back and forth for 1 second. Place slide on a slide warmer at 60 degrees Celsius for 10 minutes if a Bunsen burner is not available.

• 2

  Cool slide completely to ensure staphylococcus bacteria do not rupture or distort because of overheating.

• 3

  Check slide under light microscope to see if bacteria maintained good condition. Repeat heat-fixing with new slide if necessary.

• 4

  Don gloves to protect hands from dye.

• 5

  Place slide in staining rack over sink. Hold the slide with forceps or a clothespin if you have no staining rack.

• 6

  Flood smear with dye stain, allowing the stain to drip off.

• 7

  Rest slide on side drying rack and allow stain to dry.

• 8

  Tilt the slide at an angle over a sink and gently rinse with water, allowing the water to flow over the slide from a point above the stain.

• 9

  Blot the slide with blotting paper. Use a paper towel or absorbent pad if you have no blotting paper.

• 10

  Observe slide using light microscope to confirm stain was applied properly.