CLINICAL LAB SCIENEC

CHAPTER 15: MICROBIOLOGY 395
3. Disposable droppers or Pasteur pipettes
4. Bacterial incinerator or Bunsen burner for heat-fixing slide
5. Source of organisms such as stock cultures on agar plates or in broth (liquid
media) tubes
6. Microscope slides (do not need to be sterile but should be free of oil drops, dust,
lint, and fingerprints)
7. Forceps to handle slides being heat-fixed
8. Clean tap or deionized water
9. Waterproof sharp marker
10. Disposal containers appropriate for biohazardous waste and sharps container for
disposing of slides
Procedure
1. Wash hands and don gloves.
2. Assemble necessary equipment and supplies.
3. Turn on the bacterial incinerator at least 5 minutes before beginning the procedure.
4. Use the marker to identify a clean slide with the specimen number or patient
name. Place a drop of clean tap or deionized water onto the center of the slide.
5. Select one of the following methods for preparing smears for straining.
a. When an agar plate is the source of the organisms, gently touch the tip of a
sterile cotton or synthetic fiber swab to a bacterial colony and roll it onto the
slide, mixing it in with the drop of water (Figure 15-5Aand 15-5B).
b. When an agar plate is the source of the organisms, an inoculating needle or
loop may be used in lieu of a swab (a needle is easiest for picking from isolated
bacterial colonies). Touch the tip of the needle into a single colony of bacteria,
then insert the needle tip into the drop of water on the slide and gently roll
the needle to remove the organisms from the tip. Spread the mixture to form a
smear covering a quarter-sized area. If a loop is used, mix the loop’s contents
with the water and again spread the mixture over a quarter-sized area.
A
B
FIGURE 15-5 Making a smear from a bacterial culture on an agar plate for staining.
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