Discovery of New Trichophyton Members, T. persicum and T. spiraliforme spp. nov., as a Cause of Highly Inflammatory Tinea Cases in Iran and Czechia

Name Changes for Fungi of Medical Importance, 2020 to 2021

The current article summarizes recent changes in nomenclature for fungi of medical importance published in the years 2020 to 2021, including new species and revised names for existing ones. Many of the revised names have been widely adopted without further discussion. However, those that concern common pathogens of humans may take longer to achieve general usage, with new and current names reported together to engender increasing familiarity with the correct taxonomic classification.

Phylogenetic and ecological reevaluation of the order Onygenales

The order Onygenales is classified in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superficial, cutaneous and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by the keratin and cellulose degradation abilities. The present study aimed to investigate whether the ecological trends of the members of Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic definitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families, namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigoidaceae, were accepted in Onygenales, and two new families, Malbrancheaceae and Neogymnomycetaceae, were introduced. A number of species could not be assigned to any of the defined families. Our study provides a revised overview of the main lines of taxonomy of Onygenales, supported by multilocus analyses of ITS, LSU, TUB, TEF1, TEF3, RPB1, RPB2, and ribosomal protein 60S L10 (L1) (RP60S) sequences, combined with available data on ecology, physiology, morphology, and genomics.

Update on dermatophytosis in Mashhad, Northeastern Iran, emergence of infection with Trichophyton persicum

BACKGROUND

Dermatophytosis is a common global superficial mycosis caused by a group of keratinophilic moulds known as dermatophytes that invade the skin and keratinized tissues such as hair and nails of humans and animals. This study takes identification of a collection of clinical dermatophyte isolates by using partial sequencing of translation elongation factor-1α (Tef-1α) gene aiming both to update the epidemiological status of dermatophytosis in Mashhad, Northeastern Iran and to corroborate the efficacy of Tef-1α for species-level identification of dermatophytes.

METHOD

The demographic data related to 87 culture-positive dermatophytes isolated from patients clinically suspected to have dermatophytosis were collected. The dermatophyte isolates were subjected to a partial polymerase chain reaction (PCR)-sequencing of Tef-1α gene by using specific pan-dermatophyte primers. The data were analysed by SeqMan software, the sequences were compared and aligned with the GenBank database and the isolates were identified.

RESULTS

Identification based on Tef-1α partial sequence was successful for all isolates. The identified dermatophyte isolates in decreasing order were as Trichophyton interdigitale 19 (22%), T. tonsurans 19 (22%), T. mentagrophytes 13 (15%), T. persicum 10 (11.5%), Epidermophyton floccosum 9 (10.3%), Microsporum canis 7 (8%), T. rubrum 5 (5.7%), T. violaceum 2 (2.2%), Nannizzia fulva 2 (2.2%) and N. persicolor 1 (1.1%). The isolates have been associated with clinical forms of tinea corporis (n = 38; 43.7%), tinea faciei (n = 13; 15%), tinea cruris (n = 12; 13.9%), tinea manuum (n = 7; 8%), tinea unguium (n = 7; 8%), tinea capitis (n = 7; 8%) and tinea pedis (n = 3; 3.4%).

CONCLUSION

Dermatophytosis has yet remained a public health problem in Northeastern Iran, and infection with new and less frequent species, e.g., T. persicum, N. fulva and N. persicolor have emerged. The Tef-1α gene partial sequencing reconfirmed the resolution power of this locus for the determination of species boundaries in dermatophytes.

Subtyping Options for Microsporum canis Using Microsatellites and MLST: A Case Study from Southern Italy

Microsporum canis is considered one of the most common zoophilic dermatophyte species causing infections in animals and humans worldwide. However, molecular epidemiological studies on this dermatophyte are still rare. In this study, we aimed to analyse the population structure and relationships between M. canis strains (n = 66) collected in southern Italy and those isolated from symptomatic and asymptomatic animals (cats, dogs and rabbits) and humans. For subtyping purposes, using multilocus sequence typing (MLST) and multilocus microsatellite typing (MLMT), we first used a limited set of strains to screen for variability. No intraspecies variability was detected in six out of the eight reference genes tested and only the ITS and IGS regions showed two and three sequence genotypes, respectively, resulting in five MLST genotypes. All of eight genes were, however, useful for discrimination among M. canis, M. audouinii and M. ferrugineum. In total, eighteen microsatellite genotypes (A-R) were recognized using MLMT based on six loci, allowing a subdivision of strains into two clusters based on the Bayesian iterative algorithm. Six MLMT genotypes were from multiple host species, while 12 genotypes were found only in one host. There were no statistically significant differences between clusters in terms of host spectrum and the presence or absence of lesions. Our results confirmed that the MLST approach is not useful for detailed subtyping and examining the population structure of M. canis, while microsatellite analysis is a powerful tool for conducting surveillance studies and gaining insight into the epidemiology of infections due to this pathogen.

Re-discovery of Trichophyton bullosum in North Africa as a cause of severe dermatophytosis in donkeys

This article reports the first verified cases of infection by Trichophyton bullosum in Africa since the description of the fungus, isolated in 1933 from the coat of horses in Tunisia and Mali. We found the fungus in cutaneous samples obtained from donkeys suffering from severe dermatitis with areas of alopecia and scaling in the surroundings of Cairo (Egypt). Fungal elements (arthroconidia and hyphae) were seen at the microscopy of material collected by skin scraping and digested in NaOH. Fungal colonies grown on various culture media were identified through PCR and sequencing of the ITS rDNA region. Since the original report in Africa and the Middle East, only a few cases have been reported thus far in humans in France and two cases in horses in the Czech Republic and Japan. Trichophyton bullosum seems thus an infrequent cause of dermatophytosis. However, the actual prevalence of this pathogen may be underestimated due to the similarity with T. verrucosum, a predominant cause of infection in cattle, occasionally found on horses and donkeys. Indeed, the two fungi can be distinguished only via molecular methods, which are poorly employed in epidemiological studies on equine and bovine dermatophytosis. The present study results add to our knowledge on the ecology of this poorly explored dermatophyte, supporting the concept that equines are the primary hosts of T. bullosum and confirming the presence of this pathogen in Africa. At the same time, these are the first unequivocally documented infections in donkeys due to T. bullosum.

An Outbreak of Trichophyton quinckeanum Zoonotic Infections in the Czech Republic Transmitted from Cats and Dogs

Trichophyton quinckeanum, a zoophilic dermatophyte mostly known as the causative agent of rodent favus, is relatively rarely reported to cause human infections. Indeed, no infections were detected in Czechia between 2012 and 2015 despite routine verification of species identification by ITS rDNA sequencing. By contrast, 25 human and 11 animal cases of infection were documented from December 2016 to December 2020 and the rates tended to grow every following year. Interestingly, most of the cases were reported in the Olomouc region, suggesting a local outbreak. We bring the evidence that human T. quinckeanum infections are most commonly contracted from infected cats or, less frequently, dogs. Although rodents or contaminated soil and environment could be the source of infection to cats and dogs, the occurrence of infections in multiple animals in the same household suggests direct transmission among animals. Confirmation of the identification by molecular methods is highly recommended due to morphological similarity with T. mentagrophytes/T. interdigitale. Antifungal susceptibility testing of isolates to eight antifungals was performed using EUCAST methodology (E.Def 11.0). Among the tested antifungals, terbinafine, amorolfine, ciclopirox and efinaconazole were most potent in vitro and elevated minimum inhibitory concentrations were obtained for fluconazole and ketoconazole.