Prevalence, Risk Factors And Application Of Conventional And Molecular Diagnosis Of Superficial Fungal Infections

Abstract

Although not life-threatening, superficial fungal infection (usually caused by a dermatophyte) constitutes an important public health problem because of its high prevalence and associated morbidity. The disease can have certain negative consequences for patients, such as pain, and can potentially undermine work and social lives. In the present study, thirty six subjects attending a dermatology clinic in Cairo, Egypt were clinically examined, and samples of nails, hair and skin scales were taken. The prevalence of tinea unguium was the highest, 38.9% (25% for men and 13.9% for women), and the prevalence of tinea pedis was 30.5% (25% for men and 5.5% for women). Less frequency was recorded for tinea capitis and tinea corporis. Age distribution was significantly varied with highest number of cases in the age group of 25-40 years. Identification of isolated dermatophytes was assessed by comparing results of direct microscopic examination of KOH mounts to those of conventional cultural tests (colony morphology, microscopic examination of slide cultures. Further more, molecular diagnosis to detect the dermatophyte actin gene (ACT) fragment directly in skin, nail and hair specimens was carried out. The presence of dermatophyte ACT was investigated as an indicator of the presence of viable dermatophyte cells. Dermatophyte fungi were the predominant pathogens, but yeasts especially Candida albicans was also implicated. The etiological agents were identified as Trichopyton rubrum (39.1%), followed by Microsporum canis (17.4%). PCR sensitivity compared with direct microscopical examination of KOH mount and conventional culture methods was 95.3% and 95.8% respectively. Characterization of fungal element directly from clinical specimen by using new technique to detect molecular targets may aid in the eradication of infection as it shorten identification and treatment times and is likely to enhance compliance and reduce the costs of therapy.

New Egyptian Journal of Microbiology Vol. 17 (2) 2007: pp. 53-63