Insights into Changing Dermatophyte Spectrum in India Through Analysis of Cumulative 161,245 Cases Between 1939 and 2021

Abstract

Dermatophytosis is one of the most common superficial infections of the skin affecting nearly one-fifth of the world population at any given time. With nearly 30% of worldwide terbinafine-resistance cases in Trichophyton mentagrophytes/Trichophyton interdigitale and Trichophyton rubrum reported from India in recent years, there is a significant burden of the emerging drug resistance epidemic on India. Here, we carry out a comprehensive retrospective analysis of dermatophytosis in India using 1038 research articles pertaining to 161,245 cases reported from 1939 to 2021. We find that dermatophytosis is prevalent in all parts of the country despite variable climatic conditions in different regions. Our results show T. rubrum as the most prevalent until 2015, with a sudden change in dermatophyte spectrum towards T. mentagrophytes/T. interdigitale complex since then. We also carried out an 18S rRNA-based phylogenetics and an average nucleotide identity-and single nucleotide polymorphism-based analysis of available whole genomes and find very high relatedness among the prevalent dermatophytes, suggesting geographic specificity. The comprehensive epidemiological and phylogenomics analysis of dermatophytosis in India over the last 80 years, presented here, would help in region-specific prevention, control and treatment of dermatophyte infections, especially considering the large number of emerging resistance cases.

Molecular typing of a collection of Iranian clinical Trichophyton tonsurans isolates based on the non‐transcribed spacer region of rDNA and antifungal susceptibility testing of the species

“…13 For instance, one study found that certain haplotypes were more frequently associated with severe cases of tinea capitis, while others were more frequently associated with less severe cases. 30 Overall, haplotype analysis of T. tonsurans has provided valuable insights into its genetic diversity, population structure and evolution, as well as its interactions with human hosts and the development of antifungal drug resistance. 30 In our study, 24 haplotypes were found, eight of which were dominant and two of which were more common than the others.…”

“…30 Overall, haplotype analysis of T. tonsurans has provided valuable insights into its genetic diversity, population structure and evolution, as well as its interactions with human hosts and the development of antifungal drug resistance. 30 In our study, 24 haplotypes were found, eight of which were dominant and two of which were more common than the others.…”

“…tonsurans 13 . For instance, one study found that certain haplotypes were more frequently associated with severe cases of tinea capitis, while others were more frequently associated with less severe cases 30 . Overall, haplotype analysis of T .…”

“…Overall, haplotype analysis of T . tonsurans has provided valuable insights into its genetic diversity, population structure and evolution, as well as its interactions with human hosts and the development of antifungal drug resistance 30 …”

Dermatophyte infection: from fungal pathogenicity to host immune responses

“…rubrum is among the most frequently detected species globally and is responsible for 50%-90% of dermatophytoses (9)(10)(11)(12)(13). However, a sudden shift in the most prevalent pathogen from T. rubrum to T. mentagrophytes complex in India has been observed in recent years, which might result from advances in molecular identification (14). Other important species include Microsporum canis, Epidermophyton floccosum, and T. tonsurans (Table 1) (22,30,31).…”