How to obtain dermatophyte culture samples by using a toothbrush.
“Hair plucks can potentially miss infected hairs and may not sample infected epithelium adequately, so it is ideal to also obtain samples using the Mackenzie brush technique. With this technique, a new toothbrush is removed from its packaging and is rubbed gently over the suspect area, including the skin and haired margins of alopecic or scaly lesions. Brush the unaffected area first, and then brush the lesions to avoid spreading spores to unaffected areas and to avoid losing spores from affected areas. Then gently embed the toothbrush bristles into the fungal culture media, taking care not to embed the bristles too deeply, which risks displacing the culture media when the bristles are removed. Use a sterile hemostat to remove hair and debris caught among the bristles, and place the material on the culture medium surface.”
-Kimberly S. Coyner, DVM, DACVD