In vitro activities of 15 antifungal drugs against a large collection of clinical isolates of Microsporum canis

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.

Iranian National Survey on Tinea Capitis: Antifungal Susceptibility Profile, Epidemiological Characteristics, and Report of Two Strains with a Novel Mutation in SQLE Gene with Homology Modeling

BACKGROUND

The data on the epidemiological and antifungal susceptibility profile of tinea capitis (TC) in Iran has not been updated in recent decades. This report presents the Iranian epidemiological and drug susceptibility data regarding the distribution of dermatophytes species isolated by six national mycology centers for a period of one year (2020-2021).

MATERIAL AND METHODS

A total of 2100 clinical samples from individuals suspeted to TC were subjected to mycological analysis of direct microscopy and culture. For definite species identification, the culture isolates were additionally subjected to PCR-RFLP and PCR-sequencing of the ITS ribosomal DNA (ITS-rDNA) region. Antifungal susceptibility profiles for eight common antifungal drugs were determined by CLSI M38-A3 guidelines. The SQLE gene was partially amplified and sequenced in two terbinafine-resistant and two susceptible T. mentagrophytes isolates to elucidate probable substitutions involved in resistance.

RESULTS

TC (n = 94) was diagnosed in 75 children (79.8%) and 19 adults (20.2%) by direct microscopy and culture. Frequency of TC was significantly more among males (66 males = 70.2% vs 28 females = 29.8%). The prevalent age group affected was 5-9 years (39.36%). Thirty-two (34.04%) T. mentagrophytes, 27 (28.7%) T. tonsurans, 14 (14.9%) M. canis, 13 (13.8%) T. violaceum, 5 (5.32%) T. indotineae, 2 (2.1%) T. benhamiae, and 1 (1.1%) T. schoenleinii were identified as the causative agents. MIC values of isolates showed susceptibility to all antifungal agents, except for fluconazole and griseofulvin with GM MIC of 11.91 μg/ml and 2.01 μg/ml, respectively. Terbinafine exhibited more activity against isolates, with GM MIC 0.084 μg/ml followed by ketoconazole (0.100 μg/ml), econazole (0.107 μg/ml), itraconazole (0.133 μg/ml), butenafine (0.142 μg/ml), and miconazole (0.325 μg/ml). Two resistant T. mentagrophytes isolates harbored missense mutations in SQLE gene, corresponding to amino acid substitution F397L. Remarkably, one unique mutation, C1255T, in the SQLE sequence of two terbinafine-susceptible T. mentagrophytes strains leading to a change of leucine at the 419th position to phenylalanine (L419F) was detected.

CONCLUSIONS

T. mentagrophytes, T. tonsurans, and M. canis remained the main agents of TC in Iran, however less known species such as T. indotinea and T. benhamiae are emerging as new ones. Terbinafine could still be the appropriate choice for the treatment of diverse forms of TC.

Potential Inhibitory Effect of Miltefosine against Terbinafine-Resistant Trichophyton indotineae

Several prolonged and significant outbreaks of dermatophytosis caused by Trichophyton indotineae, a new emerging terbinafine-resistant species, have been ongoing in India in recent years, and have since spread to various countries outside Asia. Miltefosine, an alkylphosphocholine, is the most recently approved drug for the treatment of both visceral and cutaneous leishmaniasis. Miltefosine in vitro activity against terbinafine-resistant and susceptible T. mentagrophytes/T. interdigitale species complex, including T. indotineae, is limited. The current study aimed to assess miltefosine's in vitro activity against dermatophyte isolates, which are the most common causes of dermatophytosis. Miltefosine, terbinafine, butenafine, tolnaftate, and itraconazole susceptibility testing was performed using Clinical and Laboratory Standards Institute broth microdilution methods (CLSI M38-A3) against 40 terbinafine-resistant T. indotineae isolates and 40 terbinafine-susceptible T. mentagrophytes/T. interdigitale species complex isolates. Miltefosine had MIC ranges of 0.063-0.5 µg/mL and 0.125-0.25 µg/mL against both terbinafine-resistant and susceptible isolates. In terbinafine-resistant isolates, the MIC₅₀ and MIC₉₀ were 0.125 µg/mL and 0.25 µg/mL, respectively, and 0.25 µg/mL in susceptible isolates. Miltefosine had statistically significant differences in MIC results when compared to other antifungal agents (p-value 0.05) in terbinafine-resistant strains. Accordingly, the findings suggest that miltefosine has a potential activity for treating infections caused by terbinafine-resistant T. indotineae. However, further studies are needed to determine how well this in vitro activity translates into in vivo efficacy.

In vitro Activity of Allicin Alone and in Combination With Antifungal Drugs Against Microsporum canis Isolated From Patients With Tinea Capitis

The checkerboard broth method based on the Clinical and Laboratory Standards Institute M38-A3 document was used in this study to evaluate the in vitro activity of allicin alone and in combination with the antifungal drugs (griseofulvin, fluconazole, itraconazole and terbinafine) against Microsporum canis isolated from patients with tinea capitis. When allicin was used alone, only weak anti-M. canis effects were found. The MIC₅₀, MIC₉₀ and geometric mean (GM) of terbinafine were the lowest among the compounds tested. Synergism was observed for the combinations of allicin with itraconazole and terbinafine. Only indifference was observed for the combinations of allicin with griseofulvin and fluconazole. Our study illustrated the synergism of allicin in combination with itraconazole and terbinafine, which could be a reference for the treatment of tinea capitis due to M. canis.

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

Pathogens from the Trichophyton benhamiae complex are one of the most important causes of animal mycoses with significant zoonotic potential. In light of the recently revised taxonomy of this complex, we retrospectively identified 38 Trichophyton isolates that could not be resolved into any of the existing species. These strains were isolated from Iranian and Czech patients during molecular epidemiological surveys on dermatophytosis and were predominantly associated with highly inflammatory tinea corporis cases, suggesting possible zoonotic etiology. Subsequent phylogenetic (4 markers), population genetic (10 markers), and phenotypic analyses supported recognition of two novel species. The first species, Trichophyton persicum sp. nov., was identified in 36 cases of human dermatophytosis and one case of feline dermatophytosis, mainly in Southern and Western Iran. The second species, Trichophyton spiraliforme sp. nov., is only known from a single case of tinea corporis in a Czech patient who probably contracted the infection from a dog. Although the zoonotic sources of infections summarized in this study are very likely, little is known about the host spectrum of these pathogens. Awareness of these new pathogens among clinicians should refine our knowledge about their poorly explored geographic distribution. IMPORTANCE In this study, we describe two novel agents of dermatophytosis and summarize the clinical manifestation of infections. These new pathogens were discovered thanks to long-term molecular epidemiological studies conducted in Czechia and Iran. Zoonotic origins of the human infections are highly probable, but the animal hosts of these pathogens are poorly known. Further research is needed to refine our knowledge about these new dermatophytes.

RNA-Seq Analysis of the Effect of Zinc Deficiency on Microsporum canis, ZafA Gene Is Important for Growth and Pathogenicity

Microsporum canis, a common pathogenic skin fungus, can cause dermatophytosis in humans and animals. Zinc is an important trace element and plays an important role in the growth and metabolism of fungi. Currently, the effects of zinc deficiency on growth, gene expression, and metabolic pathway have not been clarified in M. canis. Therefore, M. canis was cultured under zinc restriction, and RNA-Seq was conducted in this study. The growth of M. canis was severely inhibited, and many genes showed significant upregulation and downregulation in M. canis with zinc deficiency. Zinc deficiency could negatively affect the gene expression and biological metabolic pathway in M. canis. The zinc-responsiveness transcriptional activator (ZafA) gene was significantly upregulated and shared homology with Zap1. Thus, the ZafA gene might be the main transcription factor regulating M. canis zinc homeostasis. The ZafA gene knockout strain, ZafA-hph, was constructed via Agrobacterium tumefaciens-mediated transformation (ATMT) in M. canis for the first time to assess its function. In vitro growth ability, hair biodegradation ability, virulence test, and zinc absorption capacity in ZafA-hph and wild-type M. canis strains were compared. Results showed that the ZafA gene plays an important role in zinc absorption, expression of zinc transporter genes, and growth and pathogenicity in M. canis and can be used as a new drug target. Cutting off the zinc absorption pathway can be used as a way to prevent and control infection in M. canis.

Prevalence of superficial-cutaneous fungal infections in Shiraz, Iran: A five-year retrospective study (2015-2019)

Background

Superficial and cutaneous fungal infections are common in tropical areas. The aim of this study was to provide a basic database of superficial and cutaneous mycoses and the most common etiological agents among patients.

Methods

Between 2015 and 2019, a total of 1807 patients suspected of superficial and cutaneous mycosis referring to the mycology laboratory of Shiraz medical school, Fars, Iran were evaluated. Specimens were taken from the patients’ affected area, and clinical samples were examined by direct microscopy and culture. The epidemiological profile of the patients was collected.

Results

A total of 750 patients were confirmed with mycoses. Positive samples totaled 750 cases consisting of the nail (373/49.7%), skin (323/43%), head (47/6.26%), and mucosal membrane (4/0.5%). The yeasts group included 304 Candida spp. (70.3%), 123 Malassezia spp. (28.47%), and 5 Rhodotorula spp. (1.1%). The filamentous fungi were distributed as 34.8% dermatophytes and 7.5% non‐dermatophyte. The clinical types of dermatophytosis were tinea unguium (110/261), tinea capitis (50/261), tinea pedis (48/261), tinea corporis (37/261), and tinea cruris (16/261). Non‐dermatophyte molds included A. flavus 17, A. niger 4, Aspergillus spp. 15, Penicillium. 10, Fusarium 6, Mucor 2, Stemphylium 1, and Alternaria 1.

Conclusion

This study provides useful data for the study trends of superficial and cutaneous fungal infections in a specific area. The mycological data confirmed higher incidence of candidiasis (mainly onychomycosis) and dermatophytosis in patients affected by fungal pathogens, which helped to better understand the epidemiological aspects of these mycoses.

Molecular Identification and Antifungal Susceptibility Patterns of Dermatophytes Isolated from Companion Animals with Clinical Symptoms of Dermatophytosis

Introduction

Dermatophytosis is a common skin disease in cats and dogs caused by Microsporum and Trichophyton fungi. Species identification and knowledge of their antifungal susceptibility are therapeutically and epidemiologically important. This study assessed the prevalence of feline and canine dermatophytosis in Iran, identified the aetiological agents molecularly and tested their antifungal susceptibility.

Material and Methods

A total of 308 companion animals (134 dogs and 174 cats) with skin lesions were examined from March 2015 to March 2018. Hair and skin samples were examined by microscopy with 20% KOH and cultured on Sabouraud dextrose agar with cycloheximide and chloramphenicol. Fungal isolates were confirmed by sequencing of the internal transcribed spacer (ITS) r-DNA region. The antifungal susceptibility of dermatophytes was tested by broth microdilution assay using standard drugs.

Results

Dermatophytes were found in 130 (42.2%) samples, 62 of them feline and 68 canine. Based on sequencing of all strains, M. canis (78.5%, P<0.05), M. gypseum (10.7%), and T. mentagrophytes (10.7%) were the dermatophytes isolated. The non-dermatophyte species Nannizziopsis vriesii was also isolated from two feline dermatomycosis cases. Dogs and cats younger than one year (61.5%) showed a statistically significantly higher prevalence of infection (P<0.05). Caspofungin produced the lowest geometric mean MIC at 0.0018 μg/mL, followed by ketoconazole, terbinafine, itraconazole, miconazole, griseofulvin, clotrimazole and fluconazole, in a 0.038–1.53 μg/mL range.

Conclusion

This is the first molecular study to identify the causes of pet dermatophytosis in north-western Iran. ITS-PCR was shown to be a useful and reliable method for the identification of closely related species of dermatophytes in clinical and epidemiological settings. The lowest MIC of caspofungin indicated that this drug was the most potent in vitro.

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.

Virulence and Antifungal Susceptibility of Microsporum canis Strains from Animals and Humans

The enzymatic and antifungal profiles of dermatophytes play an important role in causing infections in humans and animals. This study aimed to assess the virulence factors produced by Microsporum canis strains, in vitro antifungal profile and the relationship between virulence, antifungal profile and occurrence of lesions in animals and humans. A total of 100 M. canis strains from humans with tinea corporis (n = 10) and from animals presenting (n = 64) or not (n = 26) skin lesions was employed to evaluate phospholipase (Pz), hemolytic (Hz), lipase (Lz), catalase (Ca), and thermotolerance (GI) activities. In addition, in vitro antifungal profile was conducted using the CLSI broth microdilution method. A statistically significant difference (p < 0.05) in Lz and Ca values was revealed among strains from hosts with and without lesions. Voriconazole, terbinafine, and posaconazole were the most active drugs followed by ketoconazole, griseofulvin, itraconazole, and fluconazole in decreasing activity order. The significant positive correlation between azole susceptibility profile of M. canis and virulence factors (i.e., hemolysin and catalase) suggest that both enzyme patterns and antifungal susceptibility play a role in the appearance of skin lesions in animals and humans.

Molecular identification and antifungal susceptibility among clinical isolates of dermatophytes in Shiraz, Iran (2017-2019)

Dermatophytosis is a common superficial mycotic infection affecting individual's quality of life worldwide. The present study aimed to perform species-level identification and evaluate the antifungal susceptibility patterns of dermatophytes isolated in Shiraz, Iran. This cross-sectional study was conducted on clinical samples collected during 2017-2019 from 307 patients suspected of having dermatophytosis. The isolates were identified by direct microscopy, culture and internal transcribed spacer ribosomal DNA sequencing, and their antifungal susceptibility patterns were determined by the microdilution method. Among 307 patients, dermatophytosis was diagnosed by microscopy in 190 (61.8%) subjects and confirmed in 130 (42.3%) cases by both microscopy and culture. It was found out tinea pedis was the most common clinical manifestation, and Trichophyton mentagrophytes was the most prevalent species (28.4%), followed by T tonsurans (23.8%), Microsporum canis (11.5%), T interdigitale (10%), T verrucosum (6.9%), T rubrum (6.9%), T benhamiae (4.6%), T violaceum (3%), T simii (3%), Epidermophyton floccosum (0.7%) and M ferrugineum (0.7%). Moreover, it was revealed that luliconazole with a geometric mean (GM) minimum inhibitory concentration (MIC) of 0.03 μg ml^-1 was the most effective agent against all tested isolates. Regardless of species, 30% of isolates responded to high MICs of griseofulvin (MIC₉₀  > 2 μg ml^-1 ). The increasing prevalence of nonindigenous species of T simii, T benhamiae and M ferrugineum in Shiraz, Iran, was a notable finding. In addition, infections due to zoophilic species showed an increasing trend. These epidemiological data, along with antifungal susceptibility patterns, may have implications for clinical decision-making and successful treatment.

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.

Comparative evaluation of E-test and CLSI methods for Itraconazole, Fluconazole and Ketoconazole susceptibilities of Microsporum canis strains

The incidence of resistance to antifungal agents for dermatophytes is increasing, but most of the methods currently available to test the antifungal susceptibility of Microsporum canis still require standardization. The aims of this study were: (i) to evaluate the antifungal susceptibility of M. canis strains recovered from animals to ketoconazole (KTZ), fluconazole (FLZ) and itraconazole (ITZ) using a modified CLSI broth microdilution (CLSI M38-A2-BMD) and the E-test® protocols and (ii) to estimate the agreement between the methods. Tentative azole epidemiological cutoff values (ECVs) were also proposed in order to interpret the results of in vitro susceptibility tests and to establish the agreement between the E-test and CLSI BMD methods. A total of forty clinical M. canis strains from animals with skin lesions were tested, and the essential (EA) and categorical agreement (CA) between the two methods were determined. KTZ displayed the lowest MIC values, while ITZ and FLZ the highest. The ECV for KTZ and ITZ were 4 μg/ml, while those of FLZ was 64 μg/ml. Based on ECVs, about 88% of M. canis strains were susceptible to all azoles being a cross-resistance with ITZ-FLZ registered for one strain. A total of five M. canis strains showed MIC > ECV for FLZ using CLSI, while one strain showed MIC > ECV for ITZ using both tests. KTZ, ITZ and FLZ showed EA ranging from 92.5 to 95%, for all azoles and CA > 97% except for FLZ (87.5%). The good CA between the E-test and the CLSI BMD provides evidence of the reliability of the former method to test the antifungal susceptibility of M. canis for ITZ and KTZ and not for FLZ.

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.

Low in vitro activity of sertaconazole against clinical isolates of dermatophyte

Background and Purpose:

Dermatophytes are a group of fungi specialized in invading humans and other vertebrate keratinized tissues. These fungi cause a variety of skin, nail, and hair disorders, called dermatophytosis (tinea). In some cases, drug resistance to antifungals necessitates special treatment. Among the antifungal agents, sertaconazole (i.e., a third-generation imidazole) has a broad-spectrum against dermatophyte species. Regarding this, the present study was conducted to investigate the antifungal susceptibility of dermatophytes obtained from patients with dermatophytosis in Mashhad located in northeastern Iran.

Materials and Methods:

A total of 75 clinical dermatophyte isolates, including Trichophyton mentagrophytes (n=21), T. interdigital (n=18), T. tonsurans (n=16), Epidermophyton floccosum (n=11), Microsporum canis (n=5), Nannizzia fulvum (n=2), T. benhamiae (n=1), and T. verrucosum (n=1), were evaluated against five antifungal agents of sertaconazole, itraconazole, clotrimazole, terbinafine, and griseofulvin based on the CLSI M38-A2 guideline.

Results:

According to the results, the minimum inhibitory concentration (MIC) ranges ofsertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were estimated at 0.125-16, 0.002-1, 0.5-4, 0.031-4, and 0.016-4 µg/ml, respectively, for dermatophyte species. In addition, the geometric mean (GM) values of the MIC of sertaconazole, terbinafine, griseofulvin, itraconazole, and clotrimazole were obtained as 3.39, 1, 1.44, 1.52, and 1.93, respectively.

Conclusion:

Among the tested antifungals, terbinafine and griseofulvin were the most effective agents against dermatophyte isolates. However, sertaconazole, a third-generation imidazole, did not show any significant effect. Furthermore, M. canis and E. floccosum showed the best response to the antifungal agents.

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.

Comparison of in vitro activities of 11 antifungal agents against Trichophyton verrucosum isolates associated with a variety hosts and geographical origin

The high prevalence of dermatophytosis in animals is usually associated with extra expenditure on prevention, diagnosis and long-term treatment. Humans are usually infected from animals, also from asymptomatic carriers, through direct contact or indirectly via fungus-bearing hair, scales and fomites. Despite the medical importance of Trichophyton verrucosum infections, there are limited in vitro data on the fungal susceptibility to antifungal drugs, including new-generation triazoles, imidazoles and allyloamines. The aim of the current study was to evaluate comprehensively the in vitro activity of 11 antifungal drugs against a large collection of T. verrucosum isolates obtained in Poland, Latvia, Lithuania and Slovakia from humans and animals using a microdilution assay. In vitro susceptibility testing of 11 antifungal drugs was performed according to the Clinical and Laboratory Standards Institute (CLSI) document M38. The MICs of clotrimazole, ciclopirox, enilconazole, miconazole, naftifine and terbinafine against all T. verrucosum isolates were below 1 μg/mL, whereas those of fluconazole, griseofulvin, itraconazole, ketoconazole and voriconazole were above 1 μg/mL. Ciclopirox was demonstrated to have superior activity against all strains in comparison with the other drugs, whereas fluconazole exerted the weakest in vitro effect and exhibited the highest MIC values. Our study has shown that drugs of different chemical origin have satisfactory antifungal activity and can be promising candidates for the treatment of T. verrucosum dermatophytosis. Moreover, no significant disparity in drug sensitivity between isolates obtained from different hosts and geographical regions have been demonstrated.