The current Indian epidemic of superficial dermatophytosis due toTrichophyton mentagrophytes—A molecular study

Abstract

Summary The disease burden of chronic‐relapsing and therapy‐refractory superficial dermatophytosis dramatically increased in India within the past 5‐6 years. In order to evaluate the prevalence of this trend, 201 skin scrapings were collected from patients from all parts of India and were tested for dermatophytes using both fungal culture and a PCR‐ELISA directly performed with native skin scrapings. Fungal culture material was identified by genomic Sanger sequencing of the internal transcribed spacer (ITS) region and the translation elongation factor (TEF)‐1α gene. In total, 149 (74.13%) out of the 201 samples showed a dermatophyte‐positive culture result. Out of this, 138 (92.62%) samples were identified as Trichophyton (T.) mentagrophytes and 11 (7.38%) as Trichophyton rubrum. The PCR‐ELISA revealed similar results: 162 out of 201 (80.56%) samples were dermatophyte‐positive showing 151 (93.21%) T mentagrophytes‐ and 11 (6.79%) T rubrum‐positive samples. In this study, we show for the first time a dramatic Indian‐wide switch from T rubrum to T mentagrophytes. Additionally, sequencing revealed a solely occurring T mentagrophytes “Indian ITS genotype” that might be disseminated Indian‐wide due to the widespread abuse of topical clobetasol and other steroid molecules mixed with antifungal and antibacterial agents.

Adult tinea capitis and tinea barbae in a tertiary Portuguese hospital: A 11‐year audit

“…Albeit geographic differences have to be considered, and a 46.1% reduction in the number of diagnosed cases was observed in this study compared with a similar review realised in the past decade at another tertiary Portuguese hospital . It is clear that facial overuse of high‐strength topical steroids is a major issue perpetuating this disorder, which stands demonstrated both in our study and in others . Misdiagnosis is also very common (43%), as the condition is known to resemble folliculitis or pseudofolliculitis barbae .…”

“…5 It is clear that facial overuse of high-strength topical steroids is a major issue perpetuating this disorder, which stands demonstrated both in our study and in others. 6 Misdiagnosis is also very common (43%), as the condition is known to resemble folliculitis or pseudofolliculitis barbae. 7…”

Trichophyton mentagrophytes and T interdigitale genotypes are associated with particular geographic areas and clinical manifestations

“…Here we hypothesise that one of major selective advantages of Type VIII isolates is ability to develop antifungal drug resistance. The logical premises for the hypothesis are following: (a) Drug resistance in the TMTISG arises due to inappropriate antifungal treatment . (b) Antifungal drug resistance in clinical settings has been observed only in Type VIII isolates.…”

In vitro activities of 15 antifungal drugs against a large collection of clinical isolates of Microsporum canis

“…Previous studies have documented low in vitro susceptibility towards fluconazole, itraconazole, ketoconazole, terbinafine, naftifine, griseofulvin and ciclopirox ; clinical isolates of T rubrum and T interdigitale that are resistant to allylamines, particularly terbinafine, with point mutations in the squalene epoxidase‐encoding gene, have also been reported . Owing to problems with molecular identification, the distinction between the anthropophilic T interdigitale and zoophilic T mentagrophytes leads to some taxonomical confusion …”

“…[19][20][21] Owing to problems with molecular identification, the distinction between the anthropophilic T interdigitale and zoophilic T mentagrophytes leads to some taxonomical confusion. [22][23][24] Despite the medical importance of M. canis infections, there are limited in vitro data on the susceptibility of M. canis to antifungal drugs, 16 including new generation triazoles and imidazoles.…”