ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Namrata K. Bhosale1 , R. Prabha1, Rajesh Munuswamy2, S. Pramodhini1 and Joshy M. Easow1
1Department of Microbiology, Mahatma Gandhi Medical College and Research Institute, Puducherry – 607 402, India.
2Department of Dermatology, Venereology and Leprosy, Mahatma Gandhi Medical College and Research Institute, Puducherry – 607 402, India.
J Pure Appl Microbiol. 2022;16(2):1138-1146 | Article Number: 7462
https://doi.org/10.22207/JPAM.16.2.40 | © The Author(s). 2022
Received: 03/12/2021 | Accepted: 08/04/2022 | Published online: 27/05/2022
Issue online: June 2022
Abstract

Dermatophytosis is the superficial infection of keratinized tissue like skin, hair, and nails, in humans and animals, by a group of closely related fungi known as dermatophytes. Phenotypic identification of dermatophytes, especially through classical methods can be difficult and uncertain at times, especially when differentiating species with overlapping characteristics. Alternative identification methods based on amplification and sequence analysis of the highly polymorphic internal transcribed spacer (ITS) sequences flanking the 5.8S ribosomal RNA gene has proven to be quite sensitive and reliable. The objective of our study was to compare the phenotypic and the ITS sequencing-based methods for the identification of clinically isolated dermatophyte specimens from Puducherry, India. A total of 13 clinical samples from 39 suspected cases were found positive for dermatophytes using KOH/DMSO preparations. Specimens were subsequently cultured in Sabouraud dextrose agar (SDA) supplemented with chloramphenicol, gentamicin, and cycloheximide. Dermatophytes were identified based on culture characteristics and microscopic examination in lactophenol cotton blue preparations. ITS sequencing was additionally performed after PCR amplification for species identification. Identification based on phenotype through microscopy and culture methods confirmed infections with Trichophyton mentagrophytes (n = 11), T. rubrum (n = 1), and Microsporum gypseum (n = 1). The strains were confirmed by ITS sequencing without any discrepancy with phenotypic identification. Identification of common dermatophytes based on phenotypic characteristics may be used as a reliable method of diagnosis where sophisticated methods like ITS sequencing and PCR are unavailable.

Keywords

Dermatophytosis, ITS sequencing, Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum gypseum, dermatophytes

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