The Role of PCR in the Diagnosis of Dermatophytes in Onychomycosis

Abstract

Background:  Onychomycosis is a critical medical problem. This fungal infection of the nails leads to disfigurement, pain and impaired quality of life.  Given that it requires long-term expensive therapy; a proper diagnosis of this infection is greatly demanded.  Hence, study aimed at investigating the different laboratory methods used in the identification of dermatophytes implicated in onychomycosis including conventional laboratory methods (KOH preparation), Culture and PCR (multiplex). Subjects and Methods: This cross-section study included sixty-one (61) patients [ 82% females and 18% males]. All collected samples were investigated using microscopic examination and cultivation of samples. In addition, DNA extraction and PCR amplification were evaluated. Results: Distal and lateral subungual onychomycosis(DLSO) was the most common clinical types of onychomycosis represented 70 % of total cases. Pain was the most common presenting symptoms. Among the studied group, the most common fungal infections encountered were chronic paronychia, tinea pads and tinea manum (37.7%, 16.4%, and 8.2%) respectively. The 67.2% of the studied group by PCR were +ve, by culture 60.7% were +ve and finally, 73.8% were +ve by direct smear. The sensitivity of PCR in the diagnosis of lesions was 100% specificity was 83.3% and accuracy was 93.4%. Conclusion: The dermatophyte responsible for a majority of cases of onychomycosis. However, the role of NDMs should not be ignored and this may be now a consideration in evaluating and treating onychomycosis. PCR is highly sensitive methods for diagnosis of fungal infection. The application of PCR technology directly to the clinical specimens will allow early and accurate diagnosis of onychomycosis. This will permit prompt and targeted initiation of antifungal therapy. So, it is recommended to be used in the rapid diagnosis of onychomycosis.