Polymorphisms in the ITS rDNA regions for differentiating strains of the Trichophyton mentagrophytes complex in Sfax‐Tunisia

Abstract

The Trichophyton mentagrophytes complex is the main cause of superficial mycoses in humans and animals. Molecular research has provided useful insights into the taxonomy of this complex to overcome the challenges with conventional diagnostics. The aim of this study was to identify, type and differentiate anthropophilic and zoophilic species of the T. mentagrophytes complex. Sixty clinical samples identified as T. mentagrophytes by morphological characteristics were isolated using polymerase chain reaction-restriction fragment length polymorphism and sequence analysis of the internal transcribed spacer (ITS) regions. The identification of our strains by conventional methods was confirmed using polymerase chain reaction (PCR) sequencing in 93.34% of the cases. The strains under investigation were recategorised as T. rubrum (Tr2711). In addition, PCR products were independently digested with the restriction endonucleases, MvaI and HinfI, to produce a single dominant profile for T. interdigitale. ITS sequence analysis revealed a polymorphism in the ITS1 and 5.8S regions. Analysis of the consensus sequences distinguished four types of genotypes among our T. interdigitale species. Moreover, ITS type I was the dominant genotype characterising the anthropophilic variant of T. interdigitale. The phylogenetic study showed that only 5% of our strains were zoophilic. PCR sequencing was useful for distinguishing anthropophilic and zoophilic species of T. interdigitale, in which the differentiation is relevant because it helps to prescribe the correct treatment and to identify the surrounding source of infection.

Dermatophytes Species Isolated of HIV-Infected Patients Identified by ITS-RFLP and ITS Region Sequencing from Triangulo Mineiro, Minas Gerais State of Brazil

“…The T. interdigitale isolates herein identified presented the same restriction pattern on ITS-RFLP and were grouped together with the anthropophilic ones in the phylogenetic analysis. A recent report with 60 clinical isolates of dermatophytes showed that the most of them belonged to the anthropophilic variant of T. mentagrophytes complex [35].…”

Reconstruction of phylogenetic relationships in dermatomycete genus Trichophyton Malmsten 1848 based on ribosomal internal transcribed spacer region, partial 28S rRNA and beta‐tubulin genes sequences

“…These authors reported six sequence types. Drira et al . used scheme, identical to that by Heidemann et al .…”

“…The strain RCPF‐1278 originated from the case of tinea pedis. There are no III* sequences known from this location, and we assigned this sequence to the type III because of its origin. Our isolates RCPF‐1261, RCPF‐1425 and RCPF‐1640 could be easily attributed to the Heidemann's sequence type IV, but all lacked two additional polymorphisms, transversion G22C and insertion 217insA.…”

“…The second approach was phylogenetic reconstruction with reference sequences. In T. mentagrophytes species complex, characteristic polymorphisms were checked manually. Fifteen strains of T. interdigitale were subjected to morphological description (Table ).…”

“…Molecular techniques can offer a solution to this problem . There are several studies aimed at the search of discriminatory polymorphisms in the ribosomal ITS region of zoophilic and anthropophilic T. interdigitale isolates . The polymorphism scheme in two latter works included five sequence types, two for anthropophilic and three for zoophilic isolates.…”