The host range of dermatophytes, it is at all possible? Phenotypic evaluation of the keratinolytic activity of Trichophyton verrucosum clinical isolates

Multidrug-resistant keratinolytic dermatophytes and non-dermatophytes causing onychomycosis in outpatients

AIMS

This study identified and determined antibiograms of keratinolytic dermatophytes (DM), non-dermatophytic molds (NDM), and yeasts causing onychomycosis.

METHODS

Morphological, cultural, and biochemical characteristics were used to identify DM and NDM. The keratinolytic activity (KA) and antibiograms were conducted with keratin azure and the agar diffusion method, respectively. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined using the microdilution method.

RESULTS

Onychomycosis was more prevalent in males (53%) than females, toenails (57%) than fingernails, and commercial employees (40%) than other employees or unemployed. Fungal growth was observed in 92.5% nail samples. DM, NDM, and yeasts caused 46%, 35%, and 19% onychomycosis, respectively. Trichophyton rubrum and Trichophyton mentagrophytes were the common DM. Five different genus of NDM and three different yeasts were isolated. The KA of DM was 30-45% higher than that of NDM and yeasts. All fungal isolates (FI) were resistant to griseofulvin and fluconazole. However, 71%, 64%, and 36% of FI were sensitive to terbinafine hydrochloride, nystatin, and ketoconazole, respectively, while 84% of DM and 46% of NDM were multidrug-resistant. The MIC and MFC of these antifungals against FI ranged from micrograms to milligrams.

CONCLUSION

Multidrug resistance is growing in keratinolytic DM and NDM.

Comparative Analysis of Antifungal Susceptibility in Trichophyton Species Using Broth Microdilution Assay: A Cross-Sectional Study

Background Dermatophyte infections, predominantly caused by Trichophyton species, are a global health concern, particularly in tropical regions. The rising prevalence of resistant strains, due to the misuse of antifungal agents, necessitates robust antifungal susceptibility testing. This study aimed to evaluate antifungal susceptibility patterns of clinical isolates using the broth microdilution (BMD) assay to guide treatment strategies effectively. Methods A cross-sectional study was conducted at the All India Institute of Medical Sciences (AIIMS), Rishikesh, for over two years, including 184 clinical samples from patients with recalcitrant dermatophytosis. Samples were collected aseptically, and antifungal susceptibility testing was performed using the BMD assay. Minimum inhibitory concentration (MIC) values were analyzed for five drugs: amphotericin, terbinafine, griseofulvin, itraconazole, and fluconazole. Associations with patient demographics, potassium hydroxide (KOH) positivity, and culture outcomes were statistically assessed. Results Amphotericin showed the lowest mean MIC (0.57 µg/mL), while fluconazole exhibited the highest (7.70 µg/mL). Amphotericin and terbinafine achieved 100% inhibition, while other drugs showed 80% inhibition. Gender had no significant effect on MIC values. KOH positivity and culture outcomes significantly influenced MICs, with species-specific patterns observed. For instance, T. mentagrophytes and T. indotineae were linked to higher MICs for fluconazole and griseofulvin. Conclusion The study underscores the need for species-specific antifungal susceptibility testing to monitor resistance trends. Results focused on unexpected resistance to typically effective drugs like terbinafine or fluconazole. Routine testing and targeted stewardship are essential to improve therapeutic outcomes for dermatophytosis.

Transcriptome Analysis of Co-Cultures of THP-1 Human Macrophages with Inactivated Germinated Trichophyton rubrum Conidia

Although most mycoses are superficial, the dermatophyte Trichophyton rubrum can cause systemic infections in patients with a weakened immune system, resulting in serious and deep lesions. The aim of this study was to analyze the transcriptome of a human monocyte/macrophage cell line (THP-1) co-cultured with inactivated germinated T. rubrum conidia (IGC) in order to characterize deep infection. Analysis of macrophage viability by lactate dehydrogenase quantification showed the activation of the immune system after 24 h of contact with live germinated T. rubrum conidia (LGC). After standardization of the co-culture conditions, the release of the interleukins TNF-α, IL-8, and IL-12 was quantified. The greater release of IL-12 was observed during co-culturing of THP-1 with IGC, while there was no change in the other cytokines. Next-generation sequencing of the response to T. rubrum IGC identified the modulation of 83 genes; of these, 65 were induced and 18 were repressed. The categorization of the modulated genes showed their involvement in signal transduction, cell communication, and immune response pathways. In total, 16 genes were selected for validation and Pearson's correlation coefficient was 0.98, indicating a high correlation between RNA-seq and qPCR. Modulation of the expression of all genes was similar for LGC and IGC co-culture; however, the fold-change values were higher for LGC. Due to the high expression of the IL-32 gene in RNA-seq, we quantified this interleukin and observed an increased release in co-culture with T. rubrum. In conclusion, the macrophages-T. rubrum co-culture model revealed the ability of these cells to modulate the immune response, as demonstrated by the release of proinflammatory cytokines and the RNA-seq gene expression profile. The results obtained permit to identify possible molecular targets that are modulated in macrophages and that could be explored in antifungal therapies involving the activation of the immune system.

Circulating redox status in sheep naturally infected with Trichophyton verrucosum

Trichophyton verrucosum is a zoophilic dermatophyte that causes skin inflammation. The present study aimed to evaluate the redox status in the blood of sheep clinically infected with T. verrucosum. According to clinical and mycological investigations, 48 juvenile male Balady sheep were selected in their natural habitat and divided into four groups depending on the lesion size: mild (MID), moderate (MOD), severe (SEV) T. verrucosum infection, and healthy control groups. Compared to the controls, plasma superoxide anion increased (P < 0.05) in both MOD and SEV but total peroxides (TPx) gradually increased (P < 0.05) in MID followed by MOD and SEV. Superoxide dismutase and total antioxidant capacity (TAC) were higher (P < 0.05) in MID and lower (P < 0.05) in MOD and SEV than in controls, but SEV showed lower TAC than MOD. Malondialdehyde (MDA, a lipid peroxide marker) increased (P < 0.05) in SEV than in controls, but protein carbonyl (PC, a protein peroxidation marker) was augmented (P < 0.05) as lesions progressed from mild to severe. The oxidative stress index (TPx/TAC ratio) progressively increased (P < 0.05) in MOD and SEV. The correlation of PC was positive with TPx and negative with TAC (P < 0.01). In conclusion, sheep infection with T. verrucosum is characterized by increased TPx and decreased TAC in plasma depending on the lesion area. The redox status is shifted towards the oxidizing state, particularly in MOD and SEV cases. This results in a condition of OS, which may contribute to the pathogenesis of the disease.

Relevance of Nutrient-Sensing in the Pathogenesis of Trichophyton rubrum and Trichophyton interdigitale

The growth and development of organisms depend on nutrient availability. Dermatophytes must sense nutrient levels and adapt to the host environment to colonize human and animal keratinized tissues. Owing to the clinical importance of the Trichophyton genus, this study compared the expression profile of genes involved in metabolism, cell cycle control, and proteases in two Trichophyton species, Trichophyton rubrum, and Trichophyton interdigitale, in response to nutrients and environmental pH. In addition, we evaluated the activity of enzymes in the tricarboxylic acid, glyoxylate, and methylcitrate cycles. Moreover, the effects of interruption of the transcription factor pacC on T. interdigitale in the same conditions as for the wild-type strain were determined. Our analyses revealed specific responses in each species to the nutritional and pH variation. An improved adaptation of T. interdigitale to keratin was observed, compared with that of T. rubrum. T. rubrum growth in buffered keratin media indicated pH 8.0 as an optimal pH condition for metabolic activity, which differed from that for T. interdigitale. Tricarboxylic acid components in T. rubrum showed increased enzymatic activity and transcript accumulation. In T. interdigitale, a higher activity of enzymes in glyoxylate and methylcitrate cycles was observed, with no direct correlation to the transcriptional profile. T. interdigitale fungal metabolism suggests the requirement of anaplerotic pathways in the late cultivation period. The identified differences between T. rubrum and T. interdigitale may represent determinants for adaptation to the host and the incidence of infection with each species.

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.

Do essential oils from plants occurring in the Brazilian Caatinga biome present antifungal potential against dermatophytoses? A systematic review

The Caatinga is an exclusively Brazilian biome where semiarid climatic conditions promote singularities in adaptive biodiversity. Many aromatic species are found in this region possessing antifungal properties, which are attributed to their essential oils. Thus, we questioned whether essential plant oils found in the Caatinga present anti-dermatophytic potential. Dermatophytes are keratinophilic fungi that cause one of the most prevalent mycoses globally, skin infections known as dermatophytoses (tineas). Here, we provide a comprehensive report of the available published information, analyzing the methods used to evaluate the antifungal activity, verifying the quality of the evidence and possible clinical applications, and discussing research trends in this area. The plants studied concentrated in the genera Croton (Euphorbiaceae), Lippia (Verbenaceae), Piper (Piperaceae), and Mentha (Lamiaceae). All of the studies used in vitro tests to analyze antifungal potential, and little evidence was ascertained concerning the mechanism of antifungal action. In addition, the essential oils also evidenced drug modifying activity of conventional antifungal drugs (Ketoconazole and Terbinafine). We believe that the anti-dermatophyte potential of plant essential oils occurring within the Caatinga is underestimated and that this review will encourage future chemical-pharmacological investigations into the plants within this biome.Key points• The essential oils from plants occurring in the Caatinga Biome present unknown anti-dermatophyte potential.• The studies against dermatophyte fungi concentrate on the families Lamiaceae and Verbenaceae.• In vitro assays were used to assess the anti-dermatophyte potential of the essential oils.

Real-Time PCR as an Alternative Technique for Detection of Dermatophytes in Cattle Herds

Dermatophytes are filamentous fungi with the ability to digest and grow on keratinized substrates. The ongoing improvements in fungal detection techniques give new scope for clinical implementations in laboratories and veterinary clinics, including the monitoring of the disease and carrier status. The technologically advanced methods for dermatophyte detection include molecular methods based on PCR. In this context, the aim of this study was to carry out tests on the occurrence of dermatophytes in cattle herds using qPCR methods and a comparative analysis with conventional methods. Each sample collected from ringworm cases and from asymptomatic cattle was divided into three parts and subjected to the real-time PCR technique, direct light microscopy analysis, and culture-based methods. The use of the real-time PCR technique with pan-dermatophyte primers detected the presence of dermatophytes in the sample with a 10.84% (45% vs. 34.17%) higher efficiency than direct analysis with light microscopy. Moreover, a dermatophyte culture was obtained from all samples with a positive qPCR result. In conclusion, it seems that this method can be used with success to detect dermatophytes and monitor cowsheds in ringworm cases and carriers in cattle.

Effects of Propolis on Infectious Diseases of Medical Relevance

Infectious diseases are a significant problem affecting the public health and economic stability of societies all over the world. Treatment is available for most of these diseases; however, many pathogens have developed resistance to drugs, necessitating the development of new therapies with chemical agents, which can have serious side effects and high toxicity. In addition, the severity and aggressiveness of emerging and re-emerging diseases, such as pandemics caused by viral agents, have led to the priority of investigating new therapies to complement the treatment of different infectious diseases. Alternative and complementary medicine is widely used throughout the world due to its low cost and easy access and has been shown to provide a wide repertoire of options for the treatment of various conditions. In this work, we address the relevance of the effects of propolis on the causal pathogens of the main infectious diseases with medical relevance; the existing compiled information shows that propolis has effects on Gram-positive and Gram-negative bacteria, fungi, protozoan parasites and helminths, and viruses; however, challenges remain, such as the assessment of their effects in clinical studies for adequate and safe use.

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.

Assessment of the subtilisin gene profile in Trichophyton verrucosum isolated from human and animal dermatophytoses in two-stage multiplex PCR

AIMS

Keratin is a fibrous and recalcitrant structural protein and the third most abundant polymer in nature after cellulose and chitin. Subtilisin-like proteases (SUB) are a group of serine endoproteases, coded by seven genes (SUB1-7), which decompose keratin structures and have been isolated from dermatophytes. Herein, we identified the SUB genes in 30 clinical isolates of Trichophyton verrucosum obtained from human and animal dermatophytosis as well as asymptomatic animal carriers.

METHODS AND RESULTS

We designed and proposed a two-stage multiplex PCR technique to detect all seven genes encoding serine proteases in dermatophytes. The analysis revealed the presence SUB1 and SUB2 amplicons in all strains regardless of the host. In the group of isolates obtained from humans, all seven subtilisin genes were shown in 40% of the strains. In T. verrucosum from asymptomatic animals, none of the isolates showed the presence of all seven subtilisin genes, and only 30% had six genes. In turn, 10% of the isolates from symptomatic animals demonstrated all seven subtilisins amplicons.

CONCLUSIONS

In conclusion, the severity of infection and ability of T. verrucosum to cause dermatophytosis in humans may not be related to specific genes but their accumulation and synergistic effects of their products.

SIGNIFICANCE AND IMPACT OF THE STUDY

Dermatophytes are pathogenic filamentous fungi with capacity to attack keratinized structures such as skin, hair and nails, causing cutaneous superficial infections. Indeed, a biological characteristic of dermatophytes is their ability to invade keratin-rich tissues by producing enzymes. Various degrees of inflammatory responses can be induced exactly by the enzymes. Subtilisin-like proteases are endoproteases, which decompose keratin structures. Our study identifies SUB genes in clinical isolates of T. verrucosum obtained from human and animal dermatophytosis as well as asymptomatic animal carriers.

Epidemiology and Diagnostic Perspectives of Dermatophytoses

Dermatophytoses affect about 25% of the world population, and the filamentous fungus Trichophyton rubrum is the main causative agent of this group of diseases. Dermatomycoses are caused by pathogenic fungi that generally trigger superficial infections and that feed on keratinized substrates such as skin, hair, and nails. However, there are an increasing number of reports describing dermatophytes that invade deep layers such as the dermis and hypodermis and that can cause deep infections in diabetic and immunocompromised patients, as well as in individuals with immunodeficiency. Despite the high incidence and importance of dermatophytes in clinical mycology, the diagnosis of this type of infection is not always accurate. The conventional methods most commonly used for mycological diagnosis are based on the identification of microbiological and biochemical features. However, in view of the limitations of these conventional methods, molecular diagnostic techniques are increasingly being used because of their higher sensitivity, specificity and rapidity and have become more accessible. The most widely used molecular techniques are conventional PCR, quantitative PCR, multiplex PCR, nested, PCR, PCR-RFLP, and PCR-ELISA. Another promising technique for the identification of microorganisms is the analysis of protein profiles by MALDI-TOF MS. Molecular techniques are promising but it is necessary to improve the quality and availability of the information in genomic and proteomic databases in order to streamline the use of bioinformatics in the identification of dermatophytes of clinical interest.

Dermatophytosis with concurrent Trichophyton verrucosum and T. benhamiae in calves after long-term transport

BACKGROUND

Dermatophytosis is a common problem in cattle. The aetiological factors associated with this disease are filamentous fungi with the ability to digest and grow on keratinized substrates. In cattle, and less frequently in other domestic animals and people, the dermatophyte Trichophyton verrucosum is most commonly isolated from skin lesions. The dermatophyte Trichophyton benhamiae is an important zoonotic pathogen, and the main sources of transmission are guinea pigs and other small rodents.

OBJECTIVES

In this report, we show multispecies infection in calves (Bos taurus) after long-term transport and vaccination against trichophytosis.

ANIMALS

Sixty animals were imported of which 32 were observed to be affected with superficial infection nine to 12 days after vaccination for dermatophytosis.

METHODS AND MATERIALS

Diagnosis was made correlating the clinical signs with a micro- and macroscopic examination of cultured fungi. Molecular differentiation was used to confirm the species affiliation.

RESULTS

Eight of the calves were infected with T. verrucosum alone, and 24 calves with both T. verrucosum and T. benhamiae. We suggest that the cause of this large outbreak was immunosuppression of the animals resulting from the stress of transport and administration of vaccine.

CONCLUSION

Both T. verrucosum and T. benhamiae can be seen concurrently in cattle.

In vitro and ex vivo biofilms of dermatophytes: a new panorama for the study of antifungal drugs

This study describes an ex vivo model that creates an environment for dermatophyte biofilm growth, with features that resemble those of in vivo conditions, designing a new panorama for the study of antifungal susceptibility. Regarding planktonic susceptibility, MIC ranges were 0.125-1 µg ml^-1 for griseofulvin and 0.000097-0.25 µg ml^-1 for itraconazole and terbinafine. sMIC50 ranges were 2->512 µg ml^-1 for griseofulvin and 0.25->64 µg ml^-1 for itraconazole and terbinafine. CLSM images demonstrated a reduction in the amount of cells within the biofilm, but hyphae and conidia were still observed and biofilm biomass was maintained. SEM analysis demonstrated a retraction in the biofilm matrix, but fungal structures and water channels were preserved. These results show that ex vivo biofilms are more tolerant to antifungal drugs than in vitro biofilms, suggesting that environmental and nutritional conditions created by this ex vivo model favor biofilm growth and robustness, and hence drug tolerance.

Detection and identification of dermatophytes based on currently available methods - a comparative study

AIMS

Accurate identification of dermatophytes is essential for implementing appropriate antifungal treatment and epidemiological analysis. However, the limitations of conventional diagnostics are a frequently discussed topic, and new diagnostic techniques are constantly expanding. In this study, we assess the suitability of conventional diagnostic techniques in comparison to the real-time PCR assay and MALDI-TOF MS in detection and identification of dermatophytes.

METHODS AND RESULTS

Strains included in this study were obtained from human and animals with symptomatic, and asymptomatic infection. A direct examination revealed that 31·7 and 60·9% of samples from symptomatic patients, and 25·7 and 60% from asymptomatic animals were positive, as shown by light and fluorescence microscopy respectively. In turn, dermatophytes were isolated from 90·2 and 71·4% of these samples. The pan-dermatophyte primers in real-time PCR assay facilitated detection in 85·3 and 82·9% of the symptomatic and asymptomatic dermatophytoses respectively. Additionally, species-specific PCR assays were positive in 70·7 and 37·1% of these samples. The MALDI-TOF MS analysis yielded positive results consistent with conventional techniques in 97·2 and 72% of symptomatic and asymptomatic infections respectively.

CONCLUSIONS

Our study revealed that there is no universal diagnostic method that would be ideal in each of the cases considered. Nonetheless, conventional techniques are still the most effective and reliable tools for mycological diagnostics.

SIGNIFICANCE AND IMPACT OF THE STUDY

Dermatologists and veterinarians have difficulties in making a diagnosis of dermatophytoses based only on observed symptoms of fungal infections, as they mimic symptoms of other dermatoses. In this context, a comparative analysis of the results of diagnostics performed using conventional methods and new technologies are crucial for implementing these pioneer methods into routine laboratory practice.

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.

Host- and pathogen-dependent susceptibility and predisposition to dermatophytosis

Dermatophytes are a highly specialized group of keratinophilic and keratinolytic filamentous fungi causing a ringworm disease called dermatophytosis or superficial mycoses. Although dermatophyte infections do not threaten the host's life, they lower its quality in humans by causing discomfort related to cosmetic problems and through their epidemiological significance, whereas in farm animals they are responsible for economic losses and constitute a source of the spread of spores. Evidence from countless observational studies that have been conducted over the last 90 years indicates that dermatophytes infect humans of every age, race, gender and socioeconomic status with strikingly high rates, as well as both farmed and wild animals in various health conditions and with various epidemiological statuses. However, the prevalence of superficial fungal infections is highly variable, since it depends on several parameters associated with the infected individual and the dermatophyte, their mutual interactions, and epidemiological and geographical factors. The curious disparity in dermatophyte infection patterns has prompted many investigators to search for a link between the host, the host's predispositions and susceptibility to the disease, and the dermatophyte species and virulence. Thus, the question arises as to whether, in addition to the generally recognized factors predisposing hosts to diseases, there are some other predispositions to dermatophyte infections in a species-specific host. In this review, we describe recent findings about the mechanism of dermatophyte infections, focusing on the adaptation of the fungi to the host and conditions predisposing each side to the disease.