Utility of real-time PCR for diagnosis of dermatophytes in Indian patients with onychomycosis.

PURPOSE: Effective treatment of onychomycosis caused by dermatophytes (i.e. Trichophyton Microsporum and Epidermophyton) requires species identification and long-term systemic treatment. Traditional diagnosis of onychomycosis is based on KOH microscopy and fungal culture which have their own limitations. Molecular diagnostic methods such as real-time PCR offer shorter turnaround time, species identification and higher sensitivity. This study intended to define diagnostic ability of real-time PCR for dermatophyte detection in Indian patients with onychomycosis.

METHODS

Nail samples from 65 clinically suspected onychomycosis patients were screened by conventional methods (KOH Microscopy and fungal culture) for detection of dermatophytes. Simultaneously real-time PCR was also performed for dermatophytes identification using commercially available real-time PCR kits.

RESULTS

Out of 65 collected nail samples, dermatophytes were identified in 58 (89.23%) samples by at least one diagnostic method. KOH-Microscopy was positive in 55 (84.62%) samples while fungal culture and real-time PCR were positive in 8 (12.31%) and 43 (66.15%) samples respectively. Five (7.69%) samples were positive by all three methods. Co-infection of two dermatophytes species was detected in six (9.23%) samples by real-time PCR.

CONCLUSIONS

This study concluded that real-time PCR can be used as a diagnostic tool for dermatophyte diagnosis in onychomycosis patients and has a greater advantage as it offers lesser turnaround time and edge of species identification. Combining real-time PCR and fungal culture method provides best algorithm for detection of dermatophytes in onychomycosis patients.