Molecular Characterization of Dermatophytes Isolated in a Tertiary Care Hospital in the North Eastern Part of India

Introduction Dermatophytes are the most common cause of superficial fungal infection. They are mostly diagnosed using phenotypic methods, but recently the molecular methods seem to be gaining ground. The objective of the present study was to compare the phenotypic and genotypic methods of identification of dermatophytes and understand the feasibility of using molecular methods for routine diagnosis of dermatophytosis. Methods  Eight repertoire isolates of Trichophyton species identified using conventional phenotypic methods were sequenced using a target of the internal transcribed spacer (ITS1 & ITS2) flanking the DNA sequence 5.8S rDNA. The FASTA sequences obtained were put under the Basic Local Alignment Search Tool - Nucleotide (BLASTn) in the National Center for Biotechnology Information (NCBI) blast portal and compared with existing sequences. Results The comparison between the phenotypic and molecular methods was established in 7/8 (87.5%) of the isolates. The ITS-based sequencing was able to speciate Trichophyton rubrum but failed to differentiate between the species complexes of Trichophyton mentagrophytes and T. rubrum. Conclusion ITS-based molecular identification is unable to correctly compare phenotypic and molecular methods of identification. Moreover, due to the high polymorphism inherent in dermatophyte species complexes, ITS was unable to delineate the dermatophyte species correctly.