Use of Restriction Fragment Length Polymorphism to Rapidly Identify Dermatophyte Species Related to Dermatophytosis

Abstract

Background:Dermatophytes are a group of keratinophilic fungi worldwide, which can infect the skin, hair and nails of humans and animals. This genus includes several species that present different features of dermatophytosis. Although, laboratory diagnosis of dermatophytes is based on direct microscopy, biochemical tests and culture, these manners are expensive, time consuming and need skilled staff. Therefore, molecular methods like PCR-RFLP are the beneficial tools for identification, which are rapid and sensitive. Thus, dermatophyte species are able to generate characteristic band patterns on agarose gel electrophoresis using PCR-RFLP technique, which leads to successful identification at the species level within a 5-hour period.Objectives:The purpose of this study was to study inter- and intraspecific genomic variations for identification of clinically important dermatophyte species obtained from clinical specimens in Isfahan, Iran using PCR-RFLP.Materials and Methods:From March 2011 to August 2012, 135 clinical isolates were collected from infected patients at Isfahan, Iran. ITS1-5.8S-ITS2 region of rDNA was amplified using universal fungal primers. Subsequently, amplified products were digested by the MvaI restriction enzyme. Using discriminating band profiles on agarose gel, dermatophyte species were identified. However, DNA sequencing was used for unidentifiable strains.Results:The specimens were obtained from skin scrapings (70.3%), nail (24.4%) and hair (5.1%) clippings. Most patients were between 21 - 30 years and the ratio of male to female was 93/42. Trichophyton interdigitale was the commonest isolate (52.5%) in our findings, followed by Epidermophyton floccosum (24.4%), T. rubrum (16.2%), Microsporum canis (2.2%), T. erinacei (1.4%), T. violaceum (1.4%), T. tonsurans (0.7%) and M. gypseum (0.7%) based on PCR-RFLP.Conclusions:Combination of traditional methods and molecular techniques considerably improves identification of dermatophytes in the species level in clinical laboratories, which can lead to properly antifungal therapy and successful management of infections. However, restriction and specificity and sensitivity should be lowered and increased, respectively, to be useful for a wide variety of clinical applications.

Causative Agents of Onychomycosis: A 7‐Year Study

“…In an investigation that was performed by Mohammadi et al. , T. interdigitale, E. floccosum , and T. rubrum were the most common dermatophytes isolated from tinea unguium. They isolated one T. violaceum strain from nail infection.…”

Clinico-mycological profile of tinea capitis and its comparative response to griseofulvin versus terbinafine

“…In a number of studies performed in Iran, Didehdar [6], Abastabar [7], and Mohammadi [8] reported T. tonsurans, T. interdigitale, and M. canis as the most common frequent dermatophytes in TC, respectively. In a study carried out in a rural region in southern Ethiopia among schoolchildren, T. verrucosum was the most common pathogen of TC [21].…”

“…Several studies in Iran have identified the dermatophyte species involved in dermatophytosis, including TC, based on the molecular methods using restriction fragment length polymorphism [6-8]. The treatment of TC requires the administration of oral antifungal drugs in order to penetrate the hair shaft.…”

Hyphal wall protein 1 gene: A potential marker for the identification of different Candida species and phylogenetic analysis

“…During the last decades, the utility of the PCR-based techniques focusing on various genetic markers have gained popularity to identify the pathogenic fungi. This increased application is due to the fact that the PCR-based techniques have higher speed, sensitivity, specificity, and reproducibility, compared to the conventional methods [ 18 ]. Several authors have previously described the PCR-based procedures, which used specific primers to amplify the DNA fragment of different genes, such as pH-regulated PHR1 and PHR2 [ 19 ], mitochondrial cytochrome b [ 20 ], pH-regulated KER1 [ 21 ], and HWP1 [ 6 ] for the discrimination of C. albicans, C. dubliniensis, and C. africana .…”