[Trichophyton tonsurans-an emerging pathogen in wrestling in Germany]

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.

Clonal Outbreak of Trichophyton tonsurans Causing Tinea Capitis Among a Wrestling Team in Beijing, China

Trichophyton tonsurans mostly causes tinea capitis and tinea corporis and often associates with outbreaks among combat sports athletes. Here, we report an outbreak of tinea capitis caused by T. tonsurans among five juvenile athletes in a wrestling team in Beijing, China. Scrapings from the lesions of the five patients were performed by direct microscopic examination and fungal culture. The fungal pathogens were all identified as T. tonsurans by morphology and sequencing of the internal transcribed spacer (ITS) regions. Multilocus genotyping analysis was performed by sequencing of 13 gene loci. The sequences of these markers were identical among the five isolates, revealing a single genotype. Antifungal susceptibilities of terbinafine, itraconazole, fluconazole, ketoconazole, and amphotericin B against T. tonsurans was determined by broth microdilution method according to the Clinical and Laboratory Standards Institute M38-A3 document and these isolates were all susceptible to the common antifungal drugs treating tinea capitis.

Tinea capitis bei Kindern – ein buntes Krankheitsbild

Bei der Tinea capitis (TC) handelt es sich um eine Infektion der behaarten Kopfhaut durch Dermatophyten, ganz überwiegend durch anthropophile und zoophile Arten. Hauptsächlich sind Kinder betroffen. Die Inzidenz der TC nimmt in Deutschland aktuell aufgrund verschiedener Ursachen zu, wie z. B. der Migrationsbewegung aus Afrika und Reisen. Auch das Erregerspektrum verändert sich. Da das klinische Bild einer TC sehr unterschiedlich sein kann, sind initiale Fehldiagnosen häufig. Um diagnostische Irrtümer und unwirksame Therapieversuche zu vermeiden, sollten Pädiater:innen mit allen Aspekten der TC vertraut sein. Dazu werden die Klinik sowie die Erreger der TC erläutert; des Weiteren werden die Diagnostik sowie leitliniengerechte Therapie der TC dargestellt. Darüber hinaus werden Maßnahmen zur Verhinderung von Reinfektionen oder Infektionen anderer Kinder erklärt.

[Terbinafine-resistant dermatophytoses and onychomycosis due to Trichophyton rubrum]

BACKGROUND

In recent years, therapy-refractory courses of dermatophytoses have increasingly become the focus of attention. The most frequent pathogens are Trichophyton (T.) rubrum and T. mentagrophytes. In addition to local therapy, first-line treatment includes terbinafine, an allylamine antifungal agent that acts by inhibiting squalene epoxidase and thus interfering with ergosterol synthesis. In refractory cases, terbinafine resistance due to point mutation in the squalene epoxidase gene has been frequently detected.

OBJECTIVES

The aim is to present specific aspects in the epidemiology of dermatophytoses with terbinafine resistance and to illustrate them on the basis of four patient cases including diagnostic procedures.

MATERIALS AND METHODS

A review of handbook knowledge, a selective literature search, and a review of four patient cases were performed.

RESULTS

Detection of the terbinafine resistance was performed by in vitro testing using the breakpoint method as well as sequencing of the Trichophyton isolate and detection of the point mutation with amino acid substitution at position L393F or F397L of squalene epoxidase.

CONCLUSION

In refractory and recurrent dermatophytoses, terbinafine resistance should be considered, especially in T. mentagrophytes and T. rubrum, and in vitro resistance testing of the dermatophyte and point mutation analysis of squalene epoxidase (SQLE) should be performed. Therapeutically, intermittent administration of itraconazole in combination with antifungal local therapy is recommended. Nevertheless, a recurrent course is to be expected and long-term therapy with itraconazole is usually necessary.