[Hedgehog fungi in a dermatological office in Munich : Case reports and review]

Trichophyton erinacei infection in humans: a case report and a literature review

BACKGROUND

Trichophyton (T.) erinacei is a rare but emerging zoonotic dermatophyte that is rarely isolated as a human pathogen, with only a few cases extensively described in the literature.

PATIENTS AND METHODS

We conducted a systematic search to identify eligible articles reporting demographics, clinical characteristics, and the therapeutic approach regarding T. erinacei infection in humans.

RESULTS

168 patients affected by T. erinacei were reported in the international literature between inception and November 2023. Only 56 cases (32.1%) were fully described. The median age at diagnosis was 26 years, the female/male ratio was around 2:1. The main source of the disease was the hedgehog. The infection presented with a combination of erythema, scaly plaques, pustules, papules, vesicles, oedema, and erosion; the most common locations were the hands and the head. The most frequently conducted examination was fungal culture, but gene sequencing and mass spectrometry improved both speed and precision in the most recent diagnostic course. Topical clotrimazole and systemic terbinafine were the most chosen treatment.

CONCLUSIONS

Trichophyton erinacei should be considered in patients with erythematous scaly patches and recent contact with hedgehogs. Terbinafine should be considered as a first-line effective treatment, griseofulvin and azoles could be considered valid alternatives.

[Conventional and molecular diagnostics in onychomycosis-part 2 : Molecular identification of causative dermatophytes by polymerase chain reaction and sequence analysis of the internal transcribed spacer region of ribosomal DNA]

Dermatophyte identification using traditional methods such as optics-based direct fluorescence microscopy and culture is nowadays supplemented by molecular biological methods. The validity of dermatophyte DNA detection with direct uniplex-polymerase chain reaction-enzyme immunoassay (PCR-EIA) in nail samples was proven by sequence analysis of the ribosomal internal transcribed spacer (ITS) region. A total of 108 dermatophytes, isolated from patients with onychomycosis, were positive for Trichophyton rubrum (TR) and Trichophyton interdigitale (TI) in culture and/or uniplex-PCR-EIA. Conventional methods for dermatophyte identification were complemented by direct uniplex-PCR-EIA and sequence analysis of the ribosomal ITS region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA). Of 108 patients (average age 62, median age 73), 56 showed cultural growth with 31 of them being identified as TR and 23 as TI. There was high agreement with the sequence analysis. Surprisingly, the pathogen of a single nail sample was identified as T. quinckeanum (formerly T. mentagrophytes sensu stricto), a rare zoophilic dermatophyte in Germany. A single TI strain turned out to be a misidentified T. tonsurans based on the sequence analysis. In all, 34 of the 52 specimens lacking cultural growth were detected by PCR as TR, and 18 specimens could be identified as TI. The results of dermatophyte identification of culture-negative nail samples were also in agreement with the results of sequence analysis. Molecular biological methods are well applicable, and they show high reliability for direct dermatophyte identification in nail samples without prior cultivation. Especially for nail samples without cultural growth, PCR-based dermatophyte identification was highly specific and sensitive.

Hedgehog Dermatophytosis: Understanding Trichophyton erinacei Infection in Pet Hedgehogs and Its Implications for Human Health

Pet hedgehogs, which are increasingly favoured companions, have garnered attention due to their potential as carriers of zoonotic diseases. These small insectivorous mammals, native to Europe, Asia, and Africa, are commonly kept as pets. The encroachment of humans into hedgehog habitats has brought these animals closer to people, raising concerns about disease transmission. This article reviews the current knowledge regarding zoonotic disease associated with pet hedgehogs, with a particular focus on mycotic infections caused by Trichophyton erinacei. Data from various regions and hedgehog species are synthesised to assess the significance of pet hedgehogs as potential reservoirs and transmitters of zoonotic pathogens. Our study highlights the importance of understanding the health risks associated with pet hedgehogs and underscores the need for continued research to mitigate zoonotic disease transmission from these potentially disease-carrying companions.

[Zoophilic dermatophytes during coronavirus pandemic in Germany]

During the coronavirus pandemic, significantly more pets were probably bought and kept. This study focuses on whether more zoophilic dermatophytes have subsequently been isolated and which species predominate. In the 1‑year period from March 2020 through February 2021, all zoophilic dermatophytes from all submissions to the Mölbis laboratory were recorded. Both the cultural and the molecular evidence of fungal detection from skin scrapings, hair roots, and, in single cases, from nails, were considered. For dermatophyte DNA (Deoxyribonucleic acid) detection, an in-house polymerase chain reaction (PCR) - enzyme-linked immunosorbent assay (ELISA) was used. In distinct cases, identification of dermatophytes was confirmed by sequencing of the internal transcribed spacer (ITS) region of the rDNA, and of the gene of the translation elongation factor (TEF)-1α. In 579 (2.56%) of 22,575 samples studied in the year 2020/2021, zoophilic dermatophytes were detectable with PCR-ELISA and/or by cultivation. In comparison, the proportion of zoophilic dermatophytes was 2.03% in the 1‑year period 2014/2015, and only 1.6% in 2018/2019. The 579 zoophilic dermatophytes were identified as follows: Trichophyton (T.) benhamiae 186 (32.1%), T. mentagrophytes 173 (29.9%), T. quinckeanum 110 (19.0%), Microsporum (M.) canis 78 (13.5%), T. verrucosum 22 (3.8%), Nannizzia (N.) persicolor 8 (1.4%), T. erinacei 1 (0.2%), and T. equinum 1 (0.2%). T. benhamiae had the highest prevalence from June to September 2020, then again in December. T. quinckeanum is associated with a sharp increase in the mice population in Germany in 2020; a significant increase was found in the months September 2020 to January 2021. T. mentagrophytes had a conspicuous peak in September. Compered with that M. canis in November. Up to 50% of the dermatophytoses caused by T. mentagrophytes, T. quinckeanum, and M. canis affected children and adolescents, while in the case of T. benhamiae it was as much as two thirds. Tinea corporis was the most common, followed by tinea faciei and tinea capitis. M. canis infections affected the capillitium more frequently than the face. Zoophilic dermatophytes were increasingly isolated during the coronavirus pandemic in Germany when compared to previous year periods. In first place, the dermatophyte T. benhamiae from guinea pigs was found in children and adolescents. A significant proportion of dermatophytoses concerned adults. T. quinckeanum is an emerging pathogen in Germany with unprecedented high infection rates in 2020.

A Polyphasic Approach to Classification and Identification of Species within the Trichophyton benhamiae Complex

In recent years, considerable advances have been made in clearing up the phylogenetic relationships within the Arthrodermataceae family. However, certain closely related taxa still contain poorly resolved species boundaries. Here, we tried to elucidate the species composition of the Trichophyton benhamiae species complex using a combined approach consisting of multi-gene phylogenetic analysis based on internal transcribed spacer (ITS) and beta-tubulin (BT) gene regions, morphological analysis, and spectral comparison using MALDI-ToF. We confirmed the existence of 11 different monophyletic clades within the complex representing either species or genetically distinct groups within species. MALDI-ToF spectrometry analysis revealed that most of these clades were readily distinguishable from one another; however, some closely related sister clades, such as T. europaeum and T. japonicum, were often misidentified as their counterpart. The distinct “yellow” and “white” phenotypes of T. benhamiae do not have a clear genetic basis and should thus be considered as different morphotypes of the same species. Strains traditionally considered T. benhamiae can be divided into three main clades: (i) T. benhamiae, (ii) T. europaeum/T. japonicum, and (iii) the phylogenetically distant T. africanum. While T. europaeum and T. japonicum are distinguishable based on their genotype, spectral and morphological analysis did not provide clear delimiting characteristics.

Identification of Zoophilic Dermatophytes Using MALDI-TOF Mass Spectrometry

Dermatophytoses represent a major health burden in animals and man. Zoophilic dermatophytes usually show a high specificity to their original animal host but a zoonotic transmission is increasingly recorded. In humans, these infections elicit highly inflammatory skin lesions requiring prolonged therapy even in the immunocompetent patient. The correct identification of the causative agent is often crucial to initiate a targeted and effective therapy. To that end, matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) represents a promising tool. The objective of this study was to evaluate the reliability of species identification of zoophilic dermatophytes using MALDI-TOF MS. The investigation of isolates from veterinary clinical samples suspicious of dermatophytoses suggests a good MALDI-TOF MS based identification of the most common zoophilic dermatophyte Microsporum canis. Trichophyton (T.) spp. usually achieved scores only around the cutoff value for secure species identification because of a small number of reference spectra. Moreover, these results need to be interpreted with caution due to the close taxonomic relationship of dermatophytes being reflected in very similar spectra. In our study, the analysis of 50 clinical samples of hedgehogs revealed no correct identification using the provided databases, nor for zoophilic neither for geophilic causative agents. After DNA sequencing, adaptation of sample processing and an individual extension of the in-house database, acceptable identification scores were achieved (T. erinacei and Arthroderma spp., respectively). A score-oriented distance dendrogram revealed clustering of geophilic isolates of four different species of the genus Arthroderma and underlined the close relationship of the important zoophilic agents T. erinacei, T. verrucosum and T. benhamiae by forming a subclade within a larger cluster including different dermatophytes. Taken together, MALDI-TOF MS proofed suitable for the identification of zoophilic dermatophytes provided fresh cultures are used and the reference library was previously extended with spectra of laboratory-relevant species. Performing independent molecular methods, such as sequencing, is strongly recommended to substantiate the findings from morphologic and MALDI-TOF MS analyses, especially for uncommon causative agents.

In vitro antifungal susceptibility patterns of Trichophyton benhamiae complex isolates from diverse origin

BACKGROUND

Species from the Trichophyton benhamiae complex are mostly zoophilic dermatophytes which cause inflammatory dermatophytosis in animals and humans worldwide.

OBJECTIVES

This study was purposed to (a) to identify 169 reference and clinical dermatophyte strains from the T benhamiae complex species by molecular method and adhering to the newest taxonomy in the complex (b) to evaluate the in vitro antifungal susceptibility profile of these strains against eight common and new antifungal agents that may be used for the treatment of dermatophytosis.

METHODS

All isolates, mainly originated from Europe but also from Iran, Japan and USA, were subjected to ITS-rDNA sequencing. The in vitro antifungal susceptibility profiles of eight common and new antifungal drugs against the isolates were determined by CLSI M38-A2 protocol and according to microdilution method.

RESULTS

Based on the ITS-rDNA sequencing, T benhamiae was the dominant species (n = 102), followed by T europaeum (n = 29), T erinacei (n = 23), T japonicum (n = 10), Trichophyton sp (n = 4) and T eriotrephon (n = 1). MIC ranges across all isolates were as follows: luliconazole: 0.0002-0.002 µg/ml, terbinafine: 0.008-0.125 µg/ml, efinaconazole: 0.008-0.125 µg/ml, ciclopirox olamine: 0.03-0.5 µg/ml, itraconazole: 0.06-2 µg/ml, griseofulvin: 0.25-4 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml and tavaborole: 1-16 µg/ml.

CONCLUSION

Luliconazole, efinaconazole and terbinafine were the most potent antifungals against T benhamiae complex isolates, regardless of the geographic locations where strains were isolated. These data might help dermatologists to develop effective therapies for successful treatment of infections due to T benhamiae complex species.

Spread of Terbinafine-Resistant Trichophyton mentagrophytes Type VIII (India) in Germany-"The Tip of the Iceberg?"

Chronic recalcitrant dermatophytoses, due to Trichophyton (T.) mentagrophytes Type VIII are on the rise in India and are noteworthy for their predominance. It would not be wrong to assume that travel and migration would be responsible for the spread of T. mentagrophytes Type VIII from India, with many strains resistant to terbinafine, to other parts of the world. From September 2016 until March 2020, a total of 29 strains of T. mentagrophytes Type VIII (India) were isolated. All patients were residents of Germany: 12 females, 15 males and the gender of the remaining two was not assignable. Patients originated from India (11), Pakistan (two), Bangladesh (one), Iraq (two), Bahrain (one), Libya (one) and other unspecified countries (10). At least two patients were German-born residents. Most samples (21) were collected in 2019 and 2020. All 29 T. mentagrophytes isolates were sequenced (internal transcribed spacer (ITS) and translation elongation factor 1-α gene (TEF1-α)). All were identified as genotype VIII (India) of T. mentagrophytes. In vitro resistance testing revealed 13/29 strains (45%) to be terbinafine-resistant with minimum inhibitory concentration (MIC) breakpoints ≥0.2 µg/mL. The remaining 16 strains (55%) were terbinafine-sensitive. Point mutation analysis revealed that 10/13 resistant strains exhibited Phe³⁹⁷Leu amino acid substitution of squalene epoxidase (SQLE), indicative for in vitro resistance to terbinafine. Two resistant strains showed combined Phe³⁹⁷Leu and Ala⁴⁴⁸Thr amino acid substitutions, and one strain a single Leu³⁹³Phe amino acid substitution. Out of 16 terbinafine-sensitive strains, in eight Ala⁴⁴⁸Thr, and in one Ala⁴⁴⁸Thr +, new Val⁴⁴⁴ Ile amino acid substitutions were detected. Resistance to both itraconazole and voriconazole was observed in three out of 13 analyzed strains. Treatment included topical ciclopirox olamine plus topical miconazole or sertaconazole. Oral itraconazole 200 mg twice daily for four to eight weeks was found to be adequate. Terbinafine-resistant T. mentagrophytes Type VIII are being increasingly isolated. In Germany, transmission of T. mentagrophytes Type VIII from the Indian subcontinent to Europe should be viewed as a significant public health issue.

Epidemiology of Dermatophytoses in Switzerland According to a Survey of Dermatophytes Isolated in Lausanne between 2001 and 2018

Dermatophytes are the most common pathogenic agents of superficial mycoses in humans and animals. Knowledge of their epidemiology can facilitate the prevention of dermatophytosis and improve prophylactic measures. We sought to determine the incidence of the different dermatophyte species diagnosed in Lausanne (Switzerland) from 2001 to 2018. In total, 10,958 dermatophytes were isolated from patients and 459 from pets. Overall, 99% of tinea unguium and tinea pedis were caused by Trichophyton rubrum and Trichophyton interdigitale with a prevalence ratio of 3:1. Trichophyton violaceum and Trichophyton soudanense were mainly found in tinea capitis in patients of African and Mediterranean origin. Interestingly, while Epidermophyton floccosum and Trichophyton verrucosum were prevalent 50 years ago in an epidemiological analysis carried out in the same laboratory from 1967 to 1970, these two species were rarely detected from 2001 to 2018. Trichophyton mentagrophytes, Trichophyton benhamiae and Microsporum canis were the prevalent zoophilic pathogenic species in children and young adults. Our investigation of animal samples revealed the main reservoirs of these zoophilic species to be cats and dogs for T. mentagrophytes and M. canis, and Guinea pigs for T. benhamiae. This study provides an epidemiological overview of dermatophytoses in Switzerland to improve their surveillance.

Nannizzia incurvata as a rare cause of favus and tinea corporis in Cambodia and Vietnam

Nannizzia (N.) incurvata (formerly Microsporum incurvatum) represents a geophilic dermatophyte which has been previously classified as belonging to the species complex of N. gypsea (formerly Microsporum gypseum). A 42-year-old Vietnamese female from Saxony, Germany, suffered from tinea corporis of the right buttock after she returned from a 2-week-visit to her homeland Vietnam. From skin scrapings of lesions, N. incurvata grew on Sabouraud's dextrose agar. Treatment by ciclopirox olamine cream twice daily for 4 weeks was successful. A 6-year-old Cambodian boy living near river Mekong with contact history to chicken, dogs and cattle suffered from tinea faciei and capitis. Symptoms of the favus-like tinea capitis and tinea faciei were erythema and scaly patches with areas of alopecia. N. incurvata grew on Sabouraud's dextrose agar. The boy was treated with oral terbinafine 125 mg daily, topical miconazole cream and ketoconazole shampoo. The symptoms healed within 4 weeks of treatment. Cultivation of the samples revealed growth of N. incurvata. For confirmation of species identification, the isolates were subject to sequencing of ITS (internal transcribed spacer) region of the rDNA, and addition of the "translation elongation factor 1 α" (TEF 1 α) gene. Sequencing of the ITS region showed 100% accordance with the sequence of N. incurvata deposited at the NCBI database under the accession number MF415405. N. incurvata is a rare, or might be underdiagnosed geophilic dermatophyte described in Sri Lanka and Vietnam until now. This is the first isolation of N. incurvata in Cambodia, and the first description of favus in a child due to this dermatophyte.

Would you like to purchase a rodent with dermatophytes?

The zoophilic dermatophyte Trichophyton benhamiae has received attention due to increasing infections in human in recent years. Trichophyton benhamiae has been found on asymptomatic rodents from pet shops in several countries posing a potential risk for transmission to humans. The aim of this study was to determine the prevalence of positive dermatophyte cultures from rodents in Danish pet shops in order to clarify the magnitude of potential sources of zoophilic infections and to prevent further spread. Specimen sampling was performed in 17 Danish pet shops using the brush technique (MacKenzie technique). After incubation, cultures were sent to ITS DNA sequencing for molecular species identification. Pet shop employees were asked to fulfil a five-question survey regarding purchase and procedures of diseased animals. A total of 98 animals were sampled (N = 32 rabbits, N = 32 guinea pigs and N = 34 hamsters). Trichophyton benhamiae was found in 14/98 samples (14%); 12/32 guinea pigs (38%) were positive with T benhamiae, 2/34 (6%) hamsters and 0/32 rabbits (0%). We found that hamsters and particularly guinea pigs from Danish pet shops are common asymptomatic carriers of the dermatophyte T benhamiae. Although a larger study is warranted to test this postulate, and it raises the question if infection control measures should be implemented in pet shops.

The current Indian epidemic of superficial dermatophytosis due to Trichophyton mentagrophytes-A molecular study

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.

[Trichophyton mentagrophytes-from snow leopard to man : A molecular approach for uncovering the chain of infection]

Sources of infection for Trichophyton (T.) mentagrophytes-a zoophilic dermatophyte-comprise pet rodents (guinea pigs, mice, rabbits) and sometimes cats. Human infections due to dermatophytes after contact with zoo animals, however, are extreme rare. Four zoo keepers from Basel Zoo were diagnosed to suffer from tinea manus and tinea corporis due to T. mentagrophytes. The 22-year-old daughter of one zoo keeper was also infected with tinea corporis after having worked in the snow leopard section for one day. The strain of the index patient was confirmed by a direct uniplex-PCR-EIA and sequence analysis of the ribosomal internal transcribed spacer (ITS) region (18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA) as T. mentagrophytes. Three young snow leopards from Basel Zoo were identified as the origin of the fungal skin infection. The transmission occurred due to direct contact of the zoo keepers with the young snow leopards when removing hedgehog ticks (Ixodes hexagonus). Two adult snow leopards had developed focal alopecia of the facial region which was diagnosed as dermatomycoses due to T. mentagrophytes by the zoo veterinarians. By sequence analysis, both the strains from the animals and a single strain of the index patient showed 100% accordance proving transmission of T. mentagrophytes from animals to the zoo keepers. Molecular biological identification revealed a strong relationship to a strain of T. mentagrophytes from European mink (Mustela lutreola) from Finland. Treatment of patients was started using topical ointment with azole antifungals, and oral terbinafine 250 mg once daily for 4 weeks. Both adult snow leopards and the asymptomatic young animals were treated with oral itraconazole.