Molecular Epidemiology of Trichophyton tonsurans, the Causative Dermatophyte of the Tinea Gladiatorum Epidemic in Japan between 2011 and 2015

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

INTRODUCTION

Wrestling, considered the national sport of Iran, has gained immense popularity among Iranians. Wrestlers frequently encounter skin conditions, with dermatophyte fungal infections, particularly tinea gladiatorum (TG), being a common issue. TG, caused by the Trichophyton genus, has emerged as a major health concern for wrestlers and other contact sport athletes worldwide. This study aimed to assess the genotypic diversity and antifungal susceptibility of Trichophyton tonsurans isolates responsible for TG in Iranian wrestlers from Mazandaran province, northern Iran.

MATERIALS AND METHODS

A total of 60 clinical T. tonsurans isolates collected from various cities in Mazandaran, were included in the study. The isolates were identified through PCR-restriction fragment length polymorphism and sequencing methods. Genomic DNA was extracted from these isolates, and the non-transcribed spacer (NTS) region of ribosomal RNA (rRNA) was targeted for genotyping using newly designed primers. Haplotype analysis was performed to explore genetic diversity, and antifungal susceptibility to terbinafine (TRB) and itraconazole (ITC) was assessed.

RESULTS

The results revealed five distinct NTS types: NTS-I, NTS-II, NTS-III, NTS-IV and NTS-V, with NTS-IV being the most prevalent. The distribution of NTS types varied across different cities, suggesting potential transmission patterns among wrestlers. Antifungal susceptibility testing showed that all isolates were susceptible to TRB, while one isolate demonstrated resistance to ITC. Genotypic diversity was not correlated with antifungal susceptibility, emphasising the importance of monitoring susceptibility to ensure effective treatment. Haplotype analysis highlighted significant genetic diversity among the T. tonsurans isolates. This diversity may be attributed to factors such as human-to-human transmission, geographic location and lifestyle changes. The study's findings underscore the need for comprehensive genotypic analysis to understand the epidemiology and evolution of T. tonsurans infections in athletes.

CONCLUSION

In conclusion, this study provides valuable insights into the genotypic diversity and antifungal susceptibility of T. tonsurans isolates causing TG in Iranian wrestlers. The presence of multiple NTS types and varying susceptibility patterns highlights the complexity of T. tonsurans infections in this population. Further research is warranted to track the transmission routes and genetic evolution of T. tonsurans strains among wrestlers and develop effective control measures.

Tinea Gladiatorum: Epidemiology, Clinical Aspects, and Management

Tinea gladiatorum (TG) is a fungal skin infection that occurs among wrestlers and other contact sport athletes with a varied prevalence rate. The most common causative factor responsible as well for local outbreaks of the infection is an anthropophilic dermatophyte species—Trichophyton tonsurans (T. tonsurans). The purpose of this study was to gather current data about TG, including epidemiology, possible diagnosing methods, clinical features, treatment approaches, and potential prevention techniques. We also performed a systematic review of studies describing TG incidence. The prevalence of the disease varied from 2.4% up to 100%. That wide range of variability forces medical practitioners to update knowledge about TG and points to the fact that it still may be a diagnostic and therapeutic challenge. Spreading awareness among athletes and trainers is one of the most important preventive steps.

Genotyping of Trichophyton tonsurans strains isolated between 2016 and 2020, and terbinafine susceptibility of the species in Japan

Trichophyton tonsurans is the most prevalent fungus which causes dermatophytosis among contact sports players in Japan. We previously surveyed the epidemic of T. tonsurans in Japan from early 2000, and determined the genotypes of isolates by analysis of restriction enzyme fragment length polymorphisms in the non-transcription spacer (NTS) region of ribosomal RNA gene, which enabled discrimination of eight genotypes, namely NTS I to NTS VIII. In the present study, we performed genotyping of T. tonsurans isolated between 2016 and 2020, and investigated the trend of the epidemic and resistance of the pathogen to antibiotic terbinafine (TBF). Regardless of which contact sport they played, the genotype of all 123 strains of T. tonsurans isolated from athletes was NTS I. Genotypes NTS II and III, which were isolated in considerable numbers mainly from wrestlers between 2000 and 2015, were conspicuously absent. TBF susceptibility was screened in 237 T. tonsurans strains isolated between 2000 and 2020 with 28 of these further assessed for minimum inhibitory concentration of TBF and squalene epoxidase gene sequences. None of the strains showed TBF resistance. TBF may still be effective to control the epidemic of T. tonsurans.

Tinea corporis gladiatorum

Tinea corporis gladiatorum (TCG) is a variety of tinea corporis transmitted by repeated and close skin contacts among athletes, in particular wrestlers and judokas. Trichophyton tonsurans is the most frequently isolated dermatophyte. Cases of TCG were reported in USA, Iran, Japan, Turkey and France, where wrestling or judo are popular. No cases of TCG were reported in Italy. The typical clinical presentation of tinea corporis is not always present in TCG: a bacterial folliculitis-like appearance is not rare. Fluconazole is the therapy of choice.

Tinea capitis et barbae caused by Trichophyton tonsurans: A retrospective cohort study of an infection chain after shavings in barber shops

BACKGROUND

Tinea capitis is a highly contagious infectious disease caused by dermatophytes. In Central Europe, it is mainly caused by zoophilic dermatophytes, as, for example Microsporum (M) canis or Trichophyton (T) mentagrophytes and increasingly by anthropophilic fungi. T tonsurans was commonly related to the Tinea gladiatorum, where transmission occurred between infected persons or via contaminated floors.

OBJECTIVE

Reporting the transmission of this highly contagious dermatophyte for the first time via beard shaving and hairdressing in barber shops in Germany.

PATIENTS AND METHODS

18 young male patients developed tinea capitis and/or barbae shortly after shavings of the beard and/or hair in a barber shop. Native, cultural and molecular diagnostics as well as tissue biopsies and resistance tests were performed of skin and hair samples.

RESULTS

In all samples, T tonsurans could be identified. The medical history and the clinical picture suggest a transmission through contaminated hairdressing tools. The patients were treated with terbinafine or itraconazole in combination with or exclusively with topical antimycotics.

CONCLUSION

The transmission and a resulting increase in the incidence of infections with T tonsurans may be due to shavings with direct skin contact of insufficiently disinfected hairdressing tools. This path of infection has already been observed in Africa and is now being described for the first time in Germany. Knowledge of the pathogen and its transmission ways are essential to interrupt the chain of infection.