Application of PCR to the identification of dermatophyte fungi.

Infection of the keratinised tissues (skin, hair and nails) in man and animals by keratinophilic fungi (dermatophytes) results in dermatophytosis (also known as tinea or ringworm). As conventional laboratory procedures for the identification of dermatophytes are either slow or lack specificity, improved diagnostic methods are required. The application of nucleic acid amplification technology has made rapid and precise identification of dermatophytes possible. Recent studies have shown that when one of the four random primers (OPAA11, OPD18, OPAA17 and OPU15) was used in arbitrarily primed PCR (AP-PCR), up to 20 of the 25 dermatophyte species or subspecies under investigation could be distinguished on the basis of characteristic band patterns detected in agarose gel electrophoresis. A combination of two random primers (OPD18 and OPAA17) used in separate reaction tubes identified 23 of the 25 dermatophyte species or subspecies examined. AP-PCR provides a rapid and practical tool for identification of dermatophyte isolates that is independent of morphological and biochemical characteristics and thus enhances laboratory diagnosis of dermatophytosis.