Page 121 - LECTURE NOTES

To dispatch skin specimens to a microbiology laboratory:

1. Collect the specimen using a sterile cotton wool swab. Insert in a contained of

Amies transport medium.
2. Make smear of the material on a clean slide & allow to air-dry in a safe place

3. Label the specimens using a lead pencil. Mark the specimen HIGH RISK if from
a patient with suspected anthrax or Bubonic plague (Yersina pestis).

4. Send the specimens with a request form to reach the laboratory within about 6

hours.

5.4.2. Gram staining technique

- Required reagents;
o Crystal violet stain

o Lugol’s iodine

o Acetone – alcohol decolorizer
o Neutral red – 1g/l (0.1% w/v) or safranin

Method

1. Fix the dried smear.

Note: when the smear is for the detection of Gonococci or Meningococci, it
should be fixed with methanol for 2 minutes (this avoids damaging pus cells)

2. Cover the fixed smear with crystal violet stain for 30-60 seconds
3. Rapidly wash off the stain with clean water

Note: - when the tap water is not clean, use filtered water or clean boiled

rainwater
4. Remove excess water, and cover the smear with Lugol’s iodine for 30-60

seconds
5. Wash of the iodine with clean water

6. Decolorize rapidly (few seconds) with acetone – alcohol wash immediately
with clean water

Caution –Acetone alcohols are highly flammable therefore use it well away

form an open flame

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