Application of PCR fingerprinting using (GACA)4 primer in the rapid discrimination of dermatophytes

Superficial fungal infections have a major impact on cosmetic health, affecting more than 20-25% of the global population, which is predominantly caused by dermatophytes. As per literature search, molecular strain typing of dermatophytes has not been investigated in India. Therefore, the present study was carried out to characterise the dermatophyte species and strains by molecular methods.

To analyse the genotype variability by applying polymerase chain reaction (PCR) fingerprinting using a simple sequence repetitive oligonucleotide (GACA)4 primer to identify the species and strain variations among the dermatophytes isolated from a tertiary care centre in Chennai.

From January 2010 to December 2010, 81 dermatophytes were isolated and included for the present study. A simple sequence repetitive oligonucleotide (GACA)4 was used as a single primer in the amplification process.

The (GACA)4-based PCR successfully amplified all the clinical isolates. Trichophyton rubrum and T. rubrum var. raubitschekii produced identical band profiles, where the latter could not be differentiated from the T. rubrum, which are being reported for the first time from south India. Epidermophyton floccosum produced species-specific band profiles. Intra-species variability was not observed among the T. rubrum and E. floccosum isolates. T. mentagrophytes produced three simple, distinct band patterns, which are surprisingly different from the earlier studies.

The PCR-based genotype using the short primer is rapid and precise in direct identification of dermatophyte isolates by one-step PCR to the species level and strain discrimination of the T. mentagrophytes variants.