Tinea corporis caused by Trichophyton equinum transmitted from asymptomatic dogs to two siblings

[Trichophyton equinum meets Chanel]

The horse is the most common reservoir of Trichophyton (T.) equinum. However, this zoophilic dermatophyte only rarely causes infections in humans. The following case report describes such a case. In addition to epidemiology, treatment is described and the morphological and physiological characteristics of T. equinum are illustrated. Because of its formation of spiral hyphae and nodal organs, which has not been previously documented for this species, the isolated strain was deposited in the German Collection of Microorganisms and Cell Cultures (DSM No. 114196).

A global view on fungal infections in humans and animals: opportunistic infections and microsporidioses

After cardiovascular diseases, infectious diseases are the second most common cause of death worldwide. Although these infections are caused mainly by viruses or bacteria, a systematically growing prevalence of human and animal opportunistic fungal infections is noticeable worldwide. More attention is being paid to this problem, especially due to the growing frequency of recalcitrant and recurrent mycoses. The latter are classically divided into superficial, which are the most common type, subcutaneous, and systemic. This work discusses opportunistic fungal pathogens without proven horizontal transmission between different animal species including humans and microsporidia as spore-forming unicellular parasites related to fungi; however, with a yet undetermined taxonomic position. The review also mentions aetiological agents, risk factors, epidemiology, geographical distribution, and finally symptoms characteristic for individual disease entities. This paper provides insight into fungal infections from a global perspective and simultaneously draws attention to emerging pathogens, whose prevalence is continuously increasing. Finally, this work also takes into consideration the correct nomenclature of fungal disease entities and the importance of secondary metabolites in the pathogenesis of fungal infections.

New Reference Genes for qRT-PCR Analysis as a Potential Target for Identification of Trichophyton verrucosum in Different Culture Conditions

Dermatophytes are a group of filamentous fungi infecting skin, hair, and nails that raise great diagnostic difficulties. qRT-PCR is a reliable technique for quantifying gene expression with increasingly frequent use in mycological diagnostics. Knowledge of genes and molecular markers with potential to be used in the identification of dermatophytes is of great importance for the development of this branch of diagnostics. In this article, the suitability of six candidate reference genes (TUBB, ACTB, ADPRF, RPL2, SDHA, and EEF1A1) was investigated for gene expression analysis in the dermatophyte Trichophyton verrucosum, which was cultured in various mycological media that are commonly used in a diagnostic laboratory, i.e., Sabouraud, potato dextrose, and keratin-supplemented MM-Cove. The different culture conditions are extremely important factors for the growth and physiology of dermatophytes. Gene expression stability was evaluated using geNorm, NormFinder, BestKeeper, and RefFinder algorithms. Regarding the stability of expression, SDHA was the most stable housekeeping gene; hence, this gene is recommended for future qRT-PCR studies on T. verrucosum strains. These results allow us to conclude that the SDHA gene can be an additional good candidate as an identification target in the qRT-PCR technique.

Human and Zoonotic Dermatophytoses: Epidemiological Aspects

Introduction

Dermatophytes are a group of molds characterized by the ability to produce keratinases, thereby carving out for themselves specific ecological niches. Their traditional division into three genera, Trichophyton, Microsporum, and Epidermophyton has been expanded to nine and the species in each genus were modified. Dermatophytes are among the most prevalent causes of human and animal mycoses. Their epidemiology is influenced by various factors. These factors may be evolutive such as the predilected environment of the fungus, namely, humans (anthropophilic), animals (zoophilic), or environment (geophilic), is evolutionary and thus may require centuries to develop. Many other factors, however, result from a variety of causes, affecting the epidemiology of dermatophytoses within a shorter time frame.

Objective

This review aims at summarizing the factors that have modified the epidemiology of dermatophytoses during the last decades.

Results

Geographic and climatic conditions, demography such as age and gender, migration, socio-economic conditions, lifestyle, and the environment have had an impact on changes in the epidemiology of dermatophytoses, as have changes in the pattern of human interaction with animals, including pets, farm, and wild animals. A typical example of such changes is the increased prevalence of Trichophyton tonsurans, which spread from Latin America to the United States and subsequently becoming a frequent etiological agent of tinea capitis in Africa, Middle East, and other areas.

Conclusion

The comprehension of the epidemiology of dermatophytoses has a major bearing on their prevention and treatment. Since it is undergoing continuous changes, periodic assessments of the most recent developments of this topic are required. This article aims at providing such an overview.

Modulation of ERG gene expression in fluconazole-resistant human and animal isolates of Trichophyton verrucosum

Dermatophytes are a group of eukaryotic microorganisms characterized by high capacity to colonize keratinized structures such as the skin, hair, and nails. Over the past years, the incidence of infections caused by zoophilic species, e.g., Trichophyton verrucosum, has been increasing in some parts of the world, especially in Europe. Moreover, the emergence of recalcitrant dermatophytoses and in vitro resistant dermatophytes has become a cause of concern worldwide. Here, we analyzed the mechanisms underlying resistance to fluconazole among clinical isolates of T. verrucosum. Quantitative RT-PCR was carried out to determine the relative expression levels of mRNA transcripts of ERG3, ERG6, and ERG11 genes in the fungal samples using the housekeeping gene GAPDH as a reference. Our results showed that the upregulation of the ERG gene expression is a possible mechanism of resistance to fluconazole in this species. Furthermore, ERG11 is the most statistically significantly overexpressed gene in the pool of fluconazole-resistant T. verrucosum isolates. Additionally, we have demonstrated that exposure to fluconazole increases the levels of expression of ERG genes in fluconazole-resistant isolates of T. verrucosum. In conclusion, this study has shown one of the possible mechanisms of resistance to fluconazole among zoophilic dermatophytes, which involves the maintenance of high levels of expression of ERG genes after drug exposure.

Genetic Predisposition and its Heredity in the Context of Increased Prevalence of Dermatophytoses

Dermatophytosis is a widespread disease with high prevalence and a substantial economic burden associated with costs of treatment. The pattern of this infectious disease covers a wide spectrum from exposed individuals without symptoms to those with acutely inflammatory or non-inflammatory, chronic to invasive, and life-threatening symptoms. Moreover, the prevalence of cutaneous fungal infections is not as high as might be expected. This curious disparity in the dermatophyte infection patterns may suggest that there are individual factors that predispose to infection, with genetics as an increasingly well-known determinant. In this review, we describe recent findings about the genetic predisposition to dermatophyte infections, with focus on inheritance in families with a high frequency of dermatophyte infections and specific host-pathogen interactions. The results of studies indicating a hereditary predisposition to dermatophytoses have been challenged by many skeptics suggesting that the varied degree of pathogenicity and the ecological diversity of this group of fungi are more important in increasing sensitivity. Nonetheless, a retrospective analysis of the hereditary propensity to dermatophytoses revealed at least several proven genetic relationships such as races, CARD9 deficiency, HLA-DR4 and HLA-DR8 type and responsible genes encoding interleukin-22, β-defensin 2 and 4 as well as genetic defects in dectin-1, which increased the prevalence of the disease in families and were involved in the inheritance of the proneness in their members. In future, the Human Genome Diversity Project can contribute to elucidation of the genetic predisposition to dermatophytoses and provide more information.

A global view on fungal infections in humans and animals: infections caused by dimorphic fungi and dermatophytoses

Fungal infections are still underappreciated and their prevalence is underestimated, which renders them a serious public health problem. Realistic discussions about their distribution, symptoms, and control can improve management and diagnosis and contribute to refinement of preventive actions using currently available tools. This article represents an overview of dermatophytes and endemic fungi that cause infections in humans and animals. In addition, the impact of climate change on the fungal spread is discussed. The endemic fungal infections characterized in this article include coccidioidomycosis, histoplasmosis, blastomycosis, lobomycosis, emergomycosis and sporotrichosis. Moreover the geographic distribution of these fungi, which are known to be climate sensitive and/or limited to endemic tropical and subtropical areas, is highlighted. In turn, dermatophytes cause superficial fungal infections of skin, hairs and nails, which are the most prevalent mycoses worldwide with a high economic burden. Therefore, the possibility of causing zoonoses and reverse zoonoses by dermatophytes is highly important. In conclusion, the article illustrates the current issues of the epidemiology and distribution of fungal diseases, emphasizing the lack of public programmes for prevention and control of these types of infection.

Complementary effect of mechanism of multidrug resistance in Trichophyton mentagrophytes isolated from human dermatophytoses of animal origin

BACKGROUND

Dermatophytoses have gained interest worldwide due to the increased resistance to terbinafine and azoles and difficulty in management of these refractory diseases.

OBJECTIVES

In this study, we identified and analysed Trichophyton mentagrophytes clinical isolates obtained from humans with infections of animal origin.

METHODS

We used quantitative real-time PCR (qRT-PCR) to examine the transcriptional modulation of three MDR genes (PDR1, MDR2 and MDR4) and analysed squalene epoxidase (SQLE) gene sequences from multidrug-resistant Trichophyton mentagrophytes isolates.

RESULTS

The expression profile revealed a 2- to 12-fold increase in mRNA accumulation in the presence of any of the antifungals, compared to cells incubated without drugs. A statistically significant relationship between the isolates exposed to itraconazole and increased expression of the tested genes was revealed. Substantially lower transcription levels were noted for cells exposed to luliconazole, that is, a third-generation azole. Additionally, in the case of 50% of terbinafine-resistant strains, Leu397Phe substitution in the SQLE gene was detected. Furthermore, the reduced susceptibility to itraconazole and voriconazole was overcome by milbemycin oxime.

CONCLUSIONS

In conclusion, our study shed more light on the role of the ABC transporter family in T. mentagrophytes, which, if overexpressed, can confer resistance to single azole drugs and even cross-resistance. Finally, milbemycin oxime could be an interesting compound supporting treatment with azole drugs in the case of refractory dermatomycoses.

Tinea corporis: an updated review

Background

Tinea corporis is a common fungal infection that mimics many other annular lesions. Physicians must familiarize themselves with this condition and its treatment.

Objective

This article aimed to provide a narrative updated review on the evaluation, diagnosis, and treatment of tinea corporis.

Methods

A PubMed search was performed with Clinical Queries using the key term ‘tinea corporis.’ The search strategy included clinical trials, meta-analyses, randomized controlled trials, observational studies, and reviews. The search was restricted to the English language. The information retrieved from the mentioned search was used in the compilation of the present article.

Results

Tinea corporis typically presents as a well-demarcated, sharply circumscribed, oval or circular, mildly erythematous, scaly patch or plaque with a raised leading edge. Mild pruritus is common. The diagnosis is often clinical but can be difficult with prior use of medications, such as calcineurin inhibitors or corticosteroids. Dermoscopy is a useful and non-invasive diagnostic tool. If necessary, the diagnosis can be confirmed by microscopic examination of potassium hydroxide wet-mount preparations of skin scrapings from the active border of the lesion. Fungal culture is the gold standard to diagnose dermatophytosis especially if the diagnosis is in doubt and results of other tests are inconclusive or the infection is widespread, severe, or resistant to treatment. The standard treatment of tinea corporis is with topical antifungals. Systemic antifungal treatment is indicated if the lesion is multiple, extensive, deep, recurrent, chronic, or unresponsive to topical antifungal treatment, or if the patient is immunodeficient.

Conclusion

The diagnosis of tinea corporis is usually clinical and should pose no problem to the physician provided the lesion is typical. However, many clinical variants of tinea corporis exist, rendering the diagnosis difficult especially with prior use of medications, such as calcineurin inhibitors or corticosteroids. As such, physicians must be familiar with this condition so that an accurate diagnosis can be made and appropriate treatment initiated.

Population differentiation, antifungal susceptibility, and host range of Trichophyton mentagrophytes isolates causing recalcitrant infections in humans and animals

The major problems in determining the causative factors of the high prevalence of dermatophytoses include the lack of a well-standardized antifungal susceptibility testing method, the low consistency of in vitro and clinical minimal inhibitory concentration values, the high genomic diversity of the population, and the unclear mechanism of pathogenicity. These factors are of particular importance when the disease is recalcitrant and relapses. Herein, we identified and characterized Trichophyton mentagrophytes isolates obtained from therapy-resistant cases in humans and animals. We used genomic diversity analysis of 17 human and 27 animal clinical isolates with the MP-PCR technique, determined their phenotypic enzymatic activity and host range, and performed antifungal susceptibility testing to currently available antifungal drugs from various chemical groups. Genomic diversity values of 35.3% and 33.3% were obtained for clinical isolates from humans and animals, respectively, yet without any relationship to the host species or antifungal drug to which resistance in therapy was revealed. The highest activity of keratinase enzymes was recorded for fox, guinea pig, and human hairs. These hosts can be considered as the main species in the host range of these isolates. A phenyl morpholine derivative, i.e. amorolfine, exhibited superior activity against strains obtained from both humans and animals with the lowest MIC₅₀. Interestingly, high compliance of terbinafine in vitro resistance with clinical problems in the treatment with this substance was shown as well. The high resistance of dermatophytes to drugs is the main cause of the recalcitrance of the infection, whereas the other features of the fungus are less important.

Identification of emerging trends in the prevalence of dermatophytoses in alpacas (Vicugna pacos) farmed in Poland

The increasing number of dermatophytoses among animals observed recently in developed countries may be connected with relocation of many exotic species outside their natural living environment. Moreover, an impact on this situation may also be exerted by relapses related to limited compliance with antifungal treatment regimes. Many exotic animals, including camelids, imported to European countries are connected with cases of tuberculosis or zoophilic dermatophytoses in humans. In the present study, we identified and comprehensively analysed dermatophyte infections in alpacas from breeding farms in Poland. As part of this study, we determined the prevalence of dermatophyte infections in alpacas. The conventional and molecular mycological diagnostic procedures applied led to unambiguous identification of the aetiological factors of symptomatic dermatophytoses and asymptomatic animals, that is Trichophyton benhamiae and T. verrucosum. Furthermore, the susceptibility tests allowed choosing the best therapeutic option and revealed superior activity of allylamine drugs against all strains. Finally, in the case of strains isolated from symptomatic dermatophytoses, our study revealed a significantly higher virulence level expressed by high activity of chosen enzymes, especially related to keratinolytic and haemolytic activity. In conclusion, this report indicates that farmed alpacas can be a reservoir or vector for contagious zoophilic dermatophyte infection. For this reason, imported animals should be subjected to meticulous monitoring to detect not only symptomatic infections but also asymptomatic animals.

Major challenges and perspectives in the diagnostics and treatment of dermatophyte infections

Dermatophytes are the aetiological factors of a majority of superficial fungal infections. What distinguishes them from other pathogenic filamentous fungi is their unique ability to degrade keratin. The remarkable ability of this group of fungi to survive in different ecosystems results from their morphological and ecological diversity as well as high adaptability to changing environmental conditions. Paradoxically, despite the progress in medicine, the prevalence of dermatophyte infections is increasing from year to year. At the beginning of the third millennium, practical diagnostic and therapeutic options are still very limited. This review focuses on understanding the major problems in this aspect of dermatophyte infections and indicates future strategies and perspectives for novel approaches to identification and drugs for elimination of dermatophytes. Particular importance is placed on development of a strategy for a diagnostic pathway and implementation of rapid and reliable diagnostics methods designed by international teams. Furthermore, among compounds that currently arouse great interest, representatives of terpenoids, alkaloids, saponins, flavonoids and essential oils deserve attention. Many of these compounds are undergoing clinical trials as potential antifungal agents, and future research should focus on attempts at determination of the applicability of tested substances. Finally, the advantages and disadvantages in implementation of new diagnostic paths and medicinal substances for routine use are indicated.