Molecular epidemiology of dermatophytosis in Tehran, Iran, a clinical and microbial survey

High Prevalence of Terbinafine Resistance Among Trichophyton mentagrophytes/T. interdigitale Species Complex, a Cross-Sectional Study from 2021 to 2022 in Northern Parts of Iran

Treatment-resistant dermatophytosis caused by the members of the Trichophyton mentagrophytes/Trichophyton interdigitale species group (TMTISG) is increasing worldwide. We aimed to determine the prevalence of TMTISG in patients with dermatophytosis in two centers from north of Iran and detect the possible mutations in the squalene epoxidase (SQLE) gene in relevant terbinafine (TRB) resistant pathogenic isolates. From November 2021 to December 2022, 1960 patients suspected to dermatophytosis and referred to two mycology referral laboratories in the north of Iran were included in the study. Identification of all dermatophyte isolates was confirmed by RFLP of rDNA internal transcribed spacer (ITS) regions. Antifungal susceptibility testing against five common antifungals using the CLSI-M38-A3 protocol was performed. The TMTISG isolates resistant to TRB, were further analyzed to determine the possible mutations in the SQLE gene. Totally, 647 cases (33%) were positive for dermatophytosis of which 280 cases (43.3%) were identified as members of TMTISG. These were more frequently isolated from tinea corporis 131 (44.56%) and tinea cruris 116 (39.46%). Of 280 TMTISG isolates, 40 (14.3%) were resistant to TRB (MIC ≥ 4 µg/mL), all found to be T. indotineae in ITS sequencing. In SQLE sequencing 34 (85%) of TRB-resistant isolates had coincident mutations of Phe397Leu and Ala448Thr whereas four and two isolates had single mutations of Phe397Leu and Leu393Ser, respectively. Overall, the resistance of Iranian TMTISG isolates to TRB greatly occurred by a mutation of Phe397Leu in the SQLE gene as alone or in combination with Ala448Thr. Nevertheless, for the occurrence of in vitro resistance, only the presence of Phe397Leu mutation seems to be decisive.

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.

Trichophyton indotineae, from epidemiology to therapeutic

Trichophyton indotineae is a newly described dermatophyte species. This fungal pathogen has recently emerged in India and is responsible for chronic or recurrent widespread superficial infections. Resistance to terbinafine is frequently associated to this pathogen and is related to point mutations in the gene encoding the squalene epoxidase. T. indotineae infections have been reported outside India, highlighting the risk of worldwide diffusion of this microorganism. Species identification and antifungal susceptibility determination are key points for infection control but still remain challenging. Systemic treatment is usually required and itraconazole is frequently prescribed in case of terbinafine resistance. This review summarizes main features of T. indotineae taxonomy, epidemiology, clinical manifestations, identification, antifungal profile, treatment and prevention.

Sheep serve as a reservoir of Trichophyton mentagrophytes genotype V infection

Human infections by Trichophyton mentagrophytes occur mainly due to contact with diseased animals. In Iran, T. mentagrophytes genotype V is the most prevalent variant of the fungus. We aimed to determine the animal reservoir of T. mentagrophytes genotype V infection. The study was done on a total of 577 dermatophyte strains obtained from animals with signs of dermatophytosis and human patients. The list of extensively sampled animals included sheep, cows, cats and dogs. For human cases, epidemiological data were collected. All dermatophyte isolates from animals along with 70 human isolates morphologically similar to T. verrucosum and T. mentagrophytes genotype V were identified by rDNA internal transcribed spacer region restriction fragment length polymorphism analysis and DNA sequencing. A total of 334 animal dermatophyte strains were identified as Microsporum canis, T. mentagrophytes genotype V, T. verrucosum, Nannizzia gypsea, T. mentagrophytes genotype II*, T. mentagrophytes genotype VII, T. quinckeanum, and N. fulva. All clinical isolates identified as T. mentagrophytes genotype V originated from skin and scalp infections. Almost all veterinary isolates of T. mentagrophytes genotype V were cultured from sheep, but epidemiological data on animal-to-human transmission of T. mentagrophytes genotype V infection were limited and we found evidence in favor of interhuman transmission. In Iran, sheep maintain T. mentagrophytes genotype V population and therefore serve as animal reservoir of respective infections. The role of sheep as the source of human dermatophytosis due to T. mentagrophytes genotype V isolates is yet to be proven.

Cutaneous Fungal Infections Caused by Dermatophytes and Non-Dermatophytes: An Updated Comprehensive Review of Epidemiology, Clinical Presentations, and Diagnostic Testing

Cutaneous fungal infection of the skin and nails poses a significant global public health challenge. Dermatophyte infection, mainly caused by Trichophyton spp., is the primary pathogenic agent responsible for skin, hair, and nail infections worldwide. The epidemiology of these infections varies depending on the geographic location and specific population. However, epidemiological pattern changes have occurred over the past decade. The widespread availability of antimicrobials has led to an increased risk of promoting resistant strains through inappropriate treatment. The escalating prevalence of resistant Trichophyton spp. infections in the past decade has raised serious healthcare concerns on a global scale. Non-dermatophyte infections, on the other hand, present even greater challenges in terms of treatment due to the high failure rate of antifungal therapy. These organisms primarily target the nails, feet, and hands. The diagnosis of cutaneous fungal infections relies on clinical presentation, laboratory investigations, and other ancillary tools available in an outpatient care setting. This review aims to present an updated and comprehensive analysis of the epidemiology, clinical manifestations, and diagnostic testing methods for cutaneous fungal infections caused by dermatophytes and non-dermatophytes. An accurate diagnosis is crucial for effective management and minimizing the risk of antifungal resistance.

Phenotypic and Genotypic Identification of Dermatophytes from Mexico and Central American Countries

Dermatophytes are fungi included in the genera Trichophyton, Microsporum, Epidermophyton, Nannizzia, Paraphyton, Lophophyton, and Arthroderma. Molecular techniques have contributed to faster and more precise identification, allowing significant advances in phylogenetic studies. This work aimed to identify clinical isolates of dermatophytes through phenotypic (macro- and micromorphology and conidia size) and genotypic methods (sequences of ITS regions, genes of β tubulin (BT2), and elongation factor α (Tef-1α)) and determine the phylogenetic relationships between isolates. Ninety-four dermatophyte isolates from Costa Rica, Guatemala, Honduras, Mexico, and the Dominican Republic were studied. The isolates presented macro- and micromorphology and conidia size described for the genera Trichophyton, Microsporum, and Epidermophyton. Genotypic analysis classified the isolates into the genera Trichophyton (63.8%), Nannizzia (25.5%), Arthroderma (9.6%), and Epidermophyton (1.1%). The most frequent species were T. rubrum (26 isolates, 27.6%), T. interdigitale (26 isolates, 27.6%), and N. incurvata (11 isolates, 11.7%), N. gypsea and A. otae (nine isolates, 9.6%), among others. The genotypic methods clarified the taxonomic status of closely related species. For instance, the ITS and BT2 markers of T. rubrum/T. violaceum did not differ but the Tef-1α gene did. On the other hand, the three markers differed in T. equinum/T. tonsurans. Therefore, the ITS, BT2, and Tef-1α genes are useful for typing in phylogenetic analyses of dermatophytes, with Tef-1α being the most informative locus. It should be noted that isolate MM-474 was identified as T. tonsurans when using ITS and Tef-1α, but when using BT2, it was identified as T. rubrum. On the other hand, no significant difference was found when comparing the methods for constructing phylogenies, as the topologies were similar.

Phylogeny, Antifungal Susceptibility, and Point Mutations of SQLE Gene in Major Pathogenic Dermatophytes Isolated From Clinical Dermatophytosis

Drug resistance is one of the major challenges to skin fungal infections, especially in tropical and subtropical infections caused by dermatophytes. This study aimed to determine the antifungal susceptibility of clinically dermatophytes and evaluate point mutations in terbinafine-resistant isolates. A total number of 123 clinical dermatophyte isolates in eight species were evaluated in terms of sensitivity to seven major antifungals. Furthermore, the point mutation in squalene epoxidase (SQLE) gene responsible for terbinafine resistance was studied. The dermatophytes species were identified by morphological characteristics and confirmed by the ITS sequencing. Also, the phylogenetic tree was drawn using the RAxML analyses for 123 dermatophytes isolates. A new XXIX genotype was also found in 4 Trichophyton mentagrophytes isolates. Based on the results obtained, terbinafine was the most effective antifungal drug followed by itraconazole and voriconazole. Trichophyton rubrum and Trichophyton tonsurans were the most susceptible species (MIC₅₀ = 0.01, 0.09 μg/ml), and T. mentagrophytes was the most resistant species (MIC₅₀ = 0.125 μg/ml) to terbinafine. Of the 123 dermatophytes isolates, six isolates showed reduced susceptibility to terbinafine, and only Trichophyton indotineae had a mutation in SQLE gene as a Phe397Leu substitution. Overall, the antifungal susceptibility test is necessary for managing dermatophytosis. These results help physicians to control the course of the disease and provide further insights to select effective drugs for patients with dermatophytosis, especially in tropical and subtropical regions of the world, where dermatophytosis is still a public health problem.

A simple multiplex polymerase chain reaction assay for rapid identification of the common pathogenic dermatophytes: Trichophyton interdigitale, Trichophyton rubrum, and Epidermophyton floccosum

Background and Purpose:

The most common etiological agents of human dermatophytosis in various parts of the world are Trichophyton rubrum, Trichophyton interdigitale, and Epidermophyton floccosum. The main aim of this study was to design and evaluate a simple and straightforward multiplex polymerase chain reaction (PCR) assay for reliable identification/differentiation of these species in clinical isolates.

Materials and Methods:

The reliable sequences of several molecular targets of dermatophytes species were used to design a multiplex PCR for the identification of common pathogenic dermatophytes. The isolates and clinical specimens examined in this study included seven standard strains of dermatophytes, 101 isolates of dermatophytes and non-dermatophyte molds/yeasts which had already been identified by sequencing or PCR-restriction fragment length polymorphism (RFLP), and 155 clinical samples from patients suspected of cutaneous mycoses.

Results:

Species-specific primer pairs for T. rubrum and T. interdigitale/T. mentagrophytes were designed based on the sequence data of the translation elongation factor 1-alpha gene, and the primers for E. floccosum targeted the specific sequence of the internal transcribed spacer region (ITS). The multiplex PCR successfully detected T. rubrum, T. interdigitale/T. mentagrophytes, and E. floccosum strains that were identified by sequencing or PCR-RFLP. However, the primer pairs selected for T. interdigitale/T. mentagrophytes cross-reacted with Trichophyton tonsurans. In testing the PCR system directly for clinical samples, the proportion of positive multiplex PCR was higher than positive culture (68.1% vs. 55.4%, respectively).

Conclusion:

The multiplex assay could detect three common agents out of several causal agents of dermatophytosis, namely T. rubrum, T. interdigitale, and E. floccosum. Therefore, by adding pan-dermatophyte primers it can be used as a comprehensive detection/identification test.

Molecular diagnosis of dermatophyte isolates from canine and feline dermatophytosis in Northeast Iran

Background

Dermatophytes are the most common causes of cutaneous fungal diseases. Dermatophytosis is a common skin disorder in dogs and cats. Species identification of these fungi is important from a therapeutic and epidemiological aspect. Conventional methods used to identify dermatophyte species are often lengthy and may be inefficient in many circumstances. Recently broad varieties of several molecular DNA‐based techniques were successfully utilised for species detection of dermatophytes.

Objectives

The aim of this study was to determine the molecular detection of dermatophyte isolates from canine and feline dermatophytosis in Mashhad, Iran.

Methods

Thirty dermatophytes isolated from dogs and cats with skin lesions and one standard strain of Microsporum canis were cultured onto Mycosel agar, and then internal transcribed spacer (ITS) region of the ribosomal DNA was amplified using the universal fungal primers ITS1 and ITS4. PCR products were subjected to sequencing and sequence analysis.

Results

Based on the sequencing of the ITS1‐5.8S‐ITS2 region on all samples, all the studied strains were M. canis and their sexual stage (teleomorph) was Arthroderma otae.

Conclusions

Microsporum canis was the only species found among dogs and cats, and its high prevalence can increase the rate of transmission to humans. In practice, ITS‐PCR, with sequence analysis, is a useful and reliable method to identify and differentiate various pathogenic species, and it can be used in clinical and epidemiological fields, even for the rapid diagnosis of dermatophyte species that are closely interrelated.

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.

Epidemiology of Dermatophytes Isolated from Clinical Samples in a Hospital in Eastern Saudi Arabia: A 20-Year Survey

BACKGROUND

Dermatophytes are group of fungi that cause superficial infections via enzymes that degrade keratin in human skin. Several factors, including climate, gender, age, lifestyle, human migration, cultural habits, and socioeconomic status influence the prevalence of dermatophyte infections. We analyzed the prevalence of dermatophyte isolates in a hospital in Eastern Saudi Arabia from 2000 to 2019.

METHODS

The data on fungal cultures were obtained from the Laboratory Information System of the Mycology Laboratories at Johns Hopkins Aramco Healthcare, and were used for the analysis. Fungal isolates were examined microscopically for the presence of specialized hyphal structures and conidia. The Vitek^® MS microbial identification system (biomerieux) was used if the culture type was not identified microscopically.

RESULTS

Among the 10,021 samples analyzed, 3040 (30.33%) were positive for fungi and only 398 (3.97%) were dermatophytes. Microsporum species was the most common dermatophyte accounting for 50.5% (n = 201) followed by trichophyton with 36.9% (n = 147). The most common positive samples were scrapping (251, 63%) and hair (68, 17%). Culture positivity relative to the age groups revealed a cluster of positive dermatophyte species in children < 10 years of age with 215 (54%) of all cases and among 10-19 years of age with 60 (15) of the cases (p < 0.001). Microsporum species were the prevalent dermatophytes in patients  < 10 years of age, while Epidermophyton species were the most frequent dermatophyte species in age groups 10-19, 20-29, and 30-39 years. However, Trichophyton species were the most frequent dermatophyte species in individuals 70-79 years. The percentage of Microsporum and Trichophyton species decreased significantly over time (p < 0.001). In addition, there was a significant seasonal variation in relation to Trichophyton species. A comparison between the most frequent species showed that there was no difference in relation to gender, but there was a difference in relation to the specimen type and age group.

CONCLUSION

Dermatophytosis was common among children and adolescent with the most common samples were scrapping and hair. There was a significant reduction in Microsporum and Trichophyton species over time.

Superficial mycoses, a matter of concern: Global and Indian scenario-an updated analysis

Superficial mycoses of skin, nails and hair are among the common fungal infections. They are caused by dermatophytes, non-dermatophyte moulds, yeasts and yeast-like fungi. Such fungal infections are widespread all over the world and are predominant in tropical as well as subtropical regions. Environmental factors, such as warm, humid and pitiable hygienic conditions, are conducive for their growth and proliferation. Although it does not cause mortality, it is known to be associated with excessive morbidity which may be psychological or physical. This affects the quality of life of the infected individuals which leads to a negative impact on their occupational, emotional and social status. Such infections are increasing on a global scale and, therefore, are of serious concern worldwide. This review article covers the global and Indian scenario of superficial mycoses taking into account the historical background, aetiological agents, prevalence, cultural and environmental factors, risk factors, pathogenesis and hygienic practices for the prevention of superficial mycoses.

Familial Cases of Trichophyton benhamiae Infection Transmitted from a Guinea Pig in Iran

Trichophyton benhamiae is a zoophilic dermatophyte mainly transmitted to humans from guinea pigs. This zoophilic species can also cause dermatophytosis as reported by human contact with other animals, such as rabbit, cat, and fox. Here, we report the tinea faciei and tinea corporis cases: a 12-year-old girl and her 53-year-old father, with no history of immunodeficiency and underlying disease, caused by T. benhamiae transmitted from a guinea pig in Iran. Dermatological examination revealed several erythematous, round, scaly, and approximately 1-4-cm-diameter lesions in both patients. The girl had seven skin lesions, and her father presented two skin lesions on the front side of his neck. The girl's lesions had started 3 weeks before and her father's lesions appeared 7 days after the first clinical appearance of the lesions in the daughter. The girl had daily close contact with a guinea pig, while her father did not have any direct exposure to the pet. Examination of the lesions scraping with 10% potassium hydroxide (KOH 10%) revealed hyaline septate hyphae and arthroconidia. The dermatophyte isolated in culture was identified as T. benhamiae using molecular analysis. The patients were successfully treated using topical sertaconazole nitrate 2% cream twice a day for 4 weeks.

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.

Investigation of in vitro antifungal susceptibility testing and genetic diversity of clinical isolates of Trichophyton benhamiae and Trichophyton eriotrephon in Iran

BACKGROUND

Trichophyton benhamiae is a zoophilic dermatophyte, known as one of the causative agents of dermatophytosis.

OBJECTIVES

The purpose of this study was to explore the genotypes of T. benhamiae strains isolated from geographically different areas of Iran and also to evaluate in vitro antifungal susceptibility profile of these strains against seven antifungal drugs.

METHODS

Twenty-two strains of T. benhamiae and two strains of T. eriotrephon were isolated from patients with distinct types of dermatophytosis. DNA extraction and amplification of rDNA regions using ITS1 and ITS4 primers were conducted on the isolates. The in vitro antifungal susceptibility of posaconazole (PSC), voriconazole (VRC), itraconazole (ITC), ketoconazole (KET), caspofungin (CAS), terbinafine (TRB) and griseofulvin (GRZ) was evaluated according to CLSI M38-A2 protocol.

RESULTS

The multiple alignment of the ITS-rDNA sequences of T. benhamiae indicated a mean similarity of 99.5%, with 0-3 interspecies nucleotide difference. The geometric mean (GM) values of minimum inhibitory concentrations (MICs) and minimum effective concentrations (MECs) across the all isolates were respectively: TRB: 0.025 mg/L, PSC: 0.032 mg/L, ITC: 0.050 mg/L and VRC: 0.059 mg/L with lower values and CAS: 0.31 mg/L, KTZ: 0.56 mg/L and GRZ: 0.76 mg/L with higher values.

CONCLUSION

Diverse ITS sequence types of T. benhamiae were shown in different geographical regions of Iran. The TRB, PSC and ITC were the most effective drugs against T. benhamiae strains, respectively. Furthermore, in our study, two strains of T. eriotrephon as a scarce dermatophyte species were described.

Antifungal Activity and the Chemical and Physical Stability of Microemulsions Containing Citrus hystrix DC Leaf Oil

Citrus hystrix DC (kaffir lime) leaf oil exhibited antifungal activities against Aspergillus niger and Candida albicans. This study aimed to evaluate the antifungal activity of kaffir lime leaf oil and microemulsions containing kaffir lime oil against Trichophyton mentagrophytes var. interdigitale. The chemical components of kaffir lime leaf oil were analyzed by gas chromatography coupled with mass spectrometry. Microemulsions containing kaffir lime oil were formulated using Tween 80, propylene glycol, and water using a phase titration method. The microemulsion of kaffir lime leaf oil was evaluated for droplet size, polydispersity index, and zeta potential using a dynamic light scattering technique. The antifungal activities of kaffir lime oil and its microemulsion were investigated through macrodilution and agar well diffusion methods, respectively. The degradation of citronellal in the microemulsion was analyzed by validated UV-Visible spectrophotometry. The minimum inhibitory concentration value of kaffir lime oil was 1.08 ± 0.00 mg/mL. The microemulsion of kaffir lime leaf oil exhibited potent antifungal activity against T. mentagrophytes var. interdigitale. The size, polydispersity index, and zeta potential of freshly prepared microemulsion were 12.82 ± 0.40 nm, 0.183 ± 0.072, and −7.87 ± 0.06 mV, respectively. The microemulsion of kaffir lime leaf oil also demonstrated good physical and chemical stability at specific temperatures. The kaffir lime oil microemulsion was highly stable when stored at 4 °C and 30 °C for 1 month but was unstable at 45 °C. The microemulsion of kaffir lime leaf oil may be an alternative therapeutic against tinea pedis caused by T. mentagrophytes var. interdigitale.

[Microsporum ferrugineum-an anthropophilic dermatophyte in Germany : Case report and review of the literature]

Three boys from the same city, treated by the same dermatologist, developed tinea capitis. Two of them, 4 and 8 years old, underwent mycological diagnostic workup. However, no pathogens familiar in this country, such as Microsporum (M.) canis or Trichophyton (T.) tonsurans, were isolated, but instead that of a dermatophyte that has not been found in Germany for decades. Both dermatophyte isolates showed white-beige-brownish colonies with a flat, radiating edge and a central, verrucous curvature. The sequencing of the internal transcribed spacer (ITS) region of the rDNA confirmed the suspicion of M. ferrugineum already expressed based on the morphological picture. The anthropophilic dermatophyte occurs in the Middle East, Asia, Eastern Europe and Africa and is considered to be the cause of tinea capitis or tinea corporis in children and adolescents. In 2016, M. ferrugineum has again been isolated in Germany, probably as a result of migration movements. The fungus is strikingly isolated to martial arts, especially wrestlers. It mainly affects children and adolescents, some with a Russian-German background. The anthropophilic dermatophyte is transmitted directly from person to person, especially in the case of tinea capitis. An indirect transmission, for example, via mats in martial arts is likely.

Recent advances in the diagnosis of dermatophytosis

Dermatophytosis is a disease of global significance caused by pathogenic keratinolytic fungi called dermatophytes in both animals and humans. The recent taxonomy of dermatophytes classifies them into six pathogenic genera, namely Microsporum, Trichophyton, Epidermophyton, Nannizzia, Lophophyton and Arthroderma. It is because of the delayed diagnostic nature and low accuracy of dermatophyte detection by conventional methods that paved the path for the evolution of molecular diagnostic techniques, which provide the accurate and rapid diagnosis of dermatophytosis for an appropriate, timely antifungal therapy that prevents the nonspecific over-the-counter self-medication. This review focuses on the importance of rapid and accurate diagnosis of dermatophytosis, limitations of conventional methods, selection of targets in diagnosis, and factors affecting sensitivity and specificity of various molecular diagnostic technologies in the diagnosis of dermatophytosis. Generally, all the molecular techniques have a significant edge over the conventional methods of culture and microscopy in the dermatophytosis diagnosis. However, in mycology laboratory, the suitability of any molecular diagnostic technique in the diagnosis of dermatophytosis is driven by the requirement of time, economy, complexity, the range of species spectrum detected and the scale of diagnostic output required. Thus, various choices involved in the pursuit of a diagnosis of dermatophytosis are determined by the available conditions and the facilities in the laboratory.

Comparison of in vitro antifungal activity of novel triazoles with available antifungal agents against dermatophyte species caused tinea pedis

OBJECTIVE

Dermatophytes are a group of keratinophilic fungi that invade and infect the keratinized tissues and cause dermatophytosis. We investigated effectiveness of novel triazole (luliconazole and lanaconazole) in comparison with available antifungal agents against dermatophyte species isolated from patients with tinea pedis.

MATERIAL AND METHODS

A total of 60 dermatophytes species were isolated from the patients with tinea pedis. Identification of species was done by DNA sequencing of the ITS1-5.8S rDNA-ITS2 rDNA region. In vitro antifungal susceptibility testing with luliconazole and lanaconazole and available antifungal agent was done in accordance with the Clinical and Laboratory Standards Institute, M38-A2 document.

RESULTS

In all investigated isolates, luliconazole had the lowest minimum inhibitory concentration (MIC) (MIC range=0.0005-0.004μg/mL), while fluconazole (MIC range=0.4-64μg/mL) had the highest MICs. Geometric mean MIC was the lowest for luliconazole (0.0008μg/mL), followed by lanoconazole (0.003μg/mL), terbinafine (0.019μg/mL), itraconazole (0.085 μg/mL), ketoconazole (0.089μg/mL), econazole (0.097μg/mL), griseofulvin (0.351 μg/mL), voriconazole (0.583μg/mL) and fluconazole (11.58μg/mL).

CONCLUSION

The novel triazoles showed potent activity against dermatophytes and promising candidates for the treatment of tinea pedis caused by Trichophyton and Epidermophyton species. However, further studies are warranted to determine the clinical implications of these investigations.

She Loves Me, She Loves Me Not: On the Dualistic Asexual/Sexual Nature of Dermatophyte Fungi

Dermatophytes are ascomycetous fungi whose sexuality is greatly influenced by their ecology. Sexual reproduction is ubiquitous among soil-related geophiles and some animal-associated zoophiles. In contrast, anthropophiles are generally present as a single mating type in the population and appear to reproduce asexually. In this article, the current knowledge on the sexuality of dermatophytes including reproduction modes, mating conditions, mating type distributions and the mating type (MAT) locus is presented in the context of revised taxonomy and discussed from an evolutionary perspective.

Epidermophyton floccosum: nucleotide sequence analysis and antifungal susceptibility testing of 40 clinical isolates

Purpose. Epidermophyton floccosum is an anthropophilic dermatophyte species, which is one of the common causative agents of dermatophytosis in different parts of the world. The aim of the present investigation was to evaluate the genetic diversity of E. floccosum strains isolated from different parts of Iran and to define the in vitro susceptibility profiles of seven antifungal drugs against these clinical isolates.Methodology. Forty clinical strains of E. floccosum isolated from 40 patients with dermatophytosis were subjected to DNA extraction and PCR amplification of the ITS rDNA region using universal primers ITS1 and ITS4. The in vitro activities of griseofulvin, itraconazole, voriconazole, posaconazole, caspofungin, ketoconazole and terbinafine were determined using a broth microdilution method according to the CLSI-M-38A2 protocol.Results. A mean genetic similarity of 99.5 % was found between E. floccosum strains, with intraspecies differences ranging from 0 to 3 nt. The geometric mean (GM) MICs and minimum effective concentrations (MECs) across all isolates were, in increasing order, as follows: terbinafine (GM=0.018 mg l^-1), posaconazole (GM=0.022 mg l^-1), itraconazole (GM=0.034 mg l^-1) and voriconazole (GM=0.045 mg l^-1), which had low MICs against all tested strains, whereas caspofungin (GM=0.22 mg l^-1), ketoconazole (GM=0.41 mg l^-1) and griseofulvin (GM=0.62 mg l^-1) demonstrated higher MICs.Conclusion. Our study showed low intraspecies variation within strains of E. floccosum. Furthermore, terbinafine, posaconazole, itraconazole and voriconazole were shown to be the most potent antifungal drugs against E. floccosum strains.

Epidemiology of dermatophytosis in northeastern Iran; A subtropical region

Background and Purpose

Dermatophytes as the causative agents of dermatophytosis (ringworm) are widely spread around the world. Accurate identification of dermatophytes in one area can be particularly important for epidemiological studies. Regarding this, the aim of the present study was to describe the species spectrum of dermatophytes, isolated from patients in Mashhad city, Iran, using the molecular-based method.

Materials and Methods

This study was conducted on 79 dermatophyte isolates obtained from the human skin, hair, and nail specimens. Species identification was performed by the polymerase chain reaction-restriction fragment length polymorphism analysis of ribosomal DNA internal transcribed spacer regions using MvaI restriction enzyme.

Results

The identified species included Trichophyton mentagrophytes/T. interdigitale species complex (n=37, 46.8%), Epidermophyton floccosum (n=12, 15.2%), T. rubrum (n=8, 10.1%), Microsporum canis (n=8, 10.1%), T. violaceum (n=5, 6.3%), T. tonsurans (n=4, 5.1%), Nannizzia gypsea (n=3, 3.8%), T. benhamiae (n=1, 1.3%), and T. verrucosum (n=1, 1.3%). The clinical forms of infection were tinea corporis (n=26, 32.8%), tinea cruris (n=22, 27.8%), tinea capitis (n=10, 12.6%), tinea unguium (n=7, 9%), tinea manuum (n=6, 8%), tinea pedis (n=5, 6.3%), and tinea faciei (n=3, 3.5%).

Conclusion

As the findings indicated, T. mentagrophytes/T. interdigitale species complex had the highest prevalence, and T. benhamiae appeared to be a new emerging agent of dermatophytosis in Mashhad, northeastern Iran.

Identification of clinical dermatophyte isolates obtained from Iran by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BACKGROUND AND PURPOSE

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used to discriminate among pathogenic microorganisms in clinical laboratories. The aim of this study was to assess the utility of MALDI-TOF MS in the routine identification of clinical dermatophyte isolates obtained from various geographical regions of Iran.

MATERIALS AND METHODS

A total of 94 isolates, including Trichophyton interdigitale (n=44), T. rubrum (n=40), T. tonsurans (n=4), Microsporum canis (n=4), and Epidermophyton floccosum (n=1), were analyzed in this study. The identity of each isolate was determined by polymerase chani reaction amplification and sequencing of the internal transcribed spacer (ITS) region of nuclear-encoded ribosomal DNA and also MALDI-TOF MS. The obtained data by molecular approach were compared with MALDI-TOF MS.

RESULTS

The MALDI-TOF MS led to the identification of 44 (47%) isolates at the species level by generating the spectral score values of ≥ 2.0. However, there was not sufficient agreement between the results of the molecular-based ITS identification methods and MALDI-TOF MS in the species identification of 16 (17%) isolates. The Bruker Daltonics database was also not able to identify protein spectra related to 12 isolates (13%), including T. interdigitale (n=5), T. rubrum (n=4), M. canis (n=2), and T. tonsurans (n=1).

CONCLUSION

According to the results, the utility of MALDI-TOF MS as a routine diagnostic tool for the accurate and reliable identification of dermatophytes can be justified whenever the protein spectra of a large set of worldwide clinical isolates are included in the commercial libraries. In addition, MALDI-TOF MS can be alternatively used to construct an in-house reference database.

Tinea manuum: A report of 18 cases observed in the metropolitan area of Milan and review of the literature

OBJECTIVE

Tinea manuum is considered in Italy as an uncommon infection, although no recent epidemiological data are available.

METHODS

In the period 2000-2018, we observed in the metropolitan area of Milan 18 patients with mycologically tinea manuum.

RESULTS

The infection was monolateral in all patients and characterised by erythema and scaling; in two patients, each vesicles and pustules were present. Two patients had also onychomycosis of one fingernail. No cases of simultaneous tinea pedis were observed. As far as the job of these patients is concerned, seven of them were masseurs, three barbers, two cattlemen, two masons, one car mechanic, one florist, one maid and one veterinarian. Trichophyton rubrum was isolated in 6 patients, Microsporum canis in 4, Trichophyton gypseum in 3, Trichophyton verrucosum in 3 and Trichophyton violaceum in 2 patients.

CONCLUSION

Masseurs were the most affected. Trichophyton rubrum and Microsporum canis were the most frequent isolated dermatophytes.

Dermatophytes and dermatophytosis in the eastern and southern parts of Africa

Dermatophytosis is currently a disease of global importance and a public health burden. It is caused by dermatophytes, which attack and grow on dead animal keratin. Dermatophytes belong to three genera, namely, Epidermophyton, Microsporum, and Trichophyton. The predominant clinical forms and causative agents vary from one region of the world to another. Poor socioeconomic status, high population densities, and poor sanitary conditions are some of the factors responsible for the high prevalence of dermatophytosis in many developing countries, which include countries in southern and eastern Africa, the focus of this review. To the best of our knowledge, there is currently no review article on published findings on dermatophytosis in the eastern and southern parts of Africa. This information will be of interest to the medical and research community since the world has become a global village. This review covers published research findings in eastern and southern regions of Africa until this date. The countries covered in the current review include Kenya, Ethiopia, Tanzania, South Africa, Mozambique, Madagascar, Malawi, Rwanda, Burundi, Uganda, Zambia, Zimbabwe, and Botswana. T. violaceum is the most common human etiological agent in all the countries under review with prevalence ranging from 56.7% to 95%, except for Madagascar (M. langeronii, reclassified as M. audouinii), Uganda (M. gypseum) and Malawi (M. audouinii). Tinea capitis was the most clinical type, followed by tinea corporis. Etiological agents of animal dermatophytoses were variable in the countries where they were reported. Major risk factors for dermatophytoses are age, climatic, and socioeconomic factors.

Characterizing the clinical isolates of dermatophytes in Hamadan city, Central west of Iran, using PCR-RLFP method

OBJECTIVE

Dermatophytosis is one of the most common mycotic infections, which considered as a public health problem in the major of countries. This study evaluated the molecular epidemiology of dermatophytosis in patients referred to Farshchian hospital in Hamadan city with PCR-RFLP method.

MATERIALS AND METHODS

Four hundred and five specimens from clinically suspected patients of dermatophytosis were collected and analyzed by direct microscopic and culture. The isolates were identified by PCR-RFLP method using the MvaI restriction enzyme.

RESULTS

Of the 405 specimens, 88 specimens were positive in direct examination and culture. Among the patients, 64.8% were males and35.2% females. Tinea pedis (31.8%) was the most common type of dermatophytosis followed by tinea corporis (22.7%), tinea cruris (20.5%), tinea capitis (10.2%), tinea manuum (5.7%), tinea faciei (4.6%) and tinea unguium (4.6%). Trichophyton interdigitale (36.4%) was the most common isolate followed by Trichophyton rubrum (27.3%), Epidermophyton floccosum (17%), Trichophyton tonsurans (11.4%), Microsporum canis (4.5%), Microsporum gypseum (2.3%) and Trichophyton benhamiae (1.1%).

CONCLUSION

Our finding showed that the anthropophilic dermatophyte species causing dermatophytosis are increasing, and molecular methods are reliable assays for accurse identification of dermatophyte species in epidemiological studies.

Molecular characterization of environmental Cladosporium species isolated from Iran

Background and Purpose:

Cladosporium species are ubiquitous, saprobic, dematiaceous fungi, only infrequently associated with human and animal opportunistic infections.

Materials and Methods:

Airborne samples were collected using the settle plate method, and soil samples were obtained from a depth of 5-10 cm of the superficial soil layer. Samples were cultured on Sabouraud dextrose agar (SDA) plates, incubated at 25°C, and examined daily for fungal colonies for two to three weeks. Isolates were identified as Cladosporium species according to the macroscopic and microscopic criteria. For species differentiation, DNA from 53 isolates was extracted and subjected to amplification of the internal transcribed spacer (ITS) region followed by sequencing.

Results:

A total of 270 samples were collected from various environmental sources, of which 79 strains of Cladosporium species were isolated. The most frequent species was C. cladosporioides (50.6%), followed by C. iridis (44.3%), C. elatum (2.5%), C. peranqestum (1.3%), and C. alicinum (1.3%).

Conclusion:

The collected data can serve as baseline information for future research and may be useful in the development of preventive and educational strategies.

Molecular characterization of environmental Cladosporium species isolated from Iran

Background and Purpose

Cladosporium species are ubiquitous, saprobic, dematiaceous fungi, only infrequently associated with human and animal opportunistic infections.

Materials and Methods

Airborne samples were collected using the settle plate method, and soil samples were obtained from a depth of 5-10 cm of the superficial soil layer. Samples were cultured on Sabouraud dextrose agar (SDA) plates, incubated at 25°C, and examined daily for fungal colonies for two to three weeks. Isolates were identified as Cladosporium species according to the macroscopic and microscopic criteria. For species differentiation, DNA from 53 isolates was extracted and subjected to amplification of the internal transcribed spacer (ITS) region followed by sequencing.

Results

A total of 270 samples were collected from various environmental sources, of which 79 strains of Cladosporium species were isolated. The most frequent species was C. cladosporioides (50.6%), followed by C. iridis (44.3%), C. elatum (2.5%), C. peranqestum (1.3%), and C. alicinum (1.3%).

Conclusion

The collected data can serve as baseline information for future research and may be useful in the development of preventive and educational strategies.

Epidemiological status of dermatophytosis in Guilan, north of Iran

Background and Purpose:

The epidemiological features of dermatophytoses have been characterized in many geographical locations of Iran, but not in Guilan, North of Iran. This study was carried out to determine the distribution pattern of dermatophytoses and their relevant agents in Guilan, North of Iran, over a period of one year, from April 2010 to April 2011.

Materials and Methods:

The clinical samples of skin, hair, and nail from 889 outpatients (317 men vs. 572 women) were used for direct microscopy and culture. All the culture-positive samples were then subjected to amplification of the internal transcribed spacer (ITS) of the nuclear rDNA followed by a restriction fragment length polymorphism (RFLP) assay to verify the causative agents.

Results:

The infection was confirmed in 90 (44.3%) males and 113 (55.7%) females. The most common type of dermatophytoses was tinea cruris (42.9%), followed by tinea pedis (20.2%), tinea corporis (11.3%), tinea unguium (7.4%), tinea faciei (6.9%), tinea manuum (6.4%), and tinea capitis (4.9%). ITS-RFLP based of the identification of isolates, showed that the infections were significantly associated with anthropophilic species, of Trichophyton rubrum (41.9%), Epidermophyton floccosum (19.7%), T. tonsurans (5.4%), and T.violaceum (2%). Other causative agents were T. interdigitale (22.6%), Microsporum canis (4.9%), T. verrucosum (2.5%), and M. gypseum (1%).

Conclusion:

The higher prevalence of T. rubrum, as the agent of dermatophytoses, than other species has never been reported from Iran and is of public health concern because of the chronic nature of infections with anthropophilic species. To thoroughly investigate the epidemiological trend of dermatophytoses in Iran, further periodical and molecular-based studies are necessary.

Morpho-Molecular Characterization of Soil Inhabitant Dermatophytes from Ahvaz, Southwest of Iran, a High Occurrence of Microsporum fulvum

Occurrence and diversity of dermatophyte mycoflora in 298 soil samples from Ahvaz, Southwest of Iran was investigated by using the hair-baiting technique. The samples were collected during spring (n = 210) and autumn (n = 88) of 2015, and the fungal isolates were identified based on the macro- and micro-morphology of colonies and with further ITS-rDNA RFLP and sequencing. Totally, 60 soil samples (20.1%) were positive for dermatophyte growth whose pH varied from 7.0 to 7.9. The highest (26.6%) and the lowest (14.3%) recovery rates were from the animal resorts and the streets soils samples, respectively. Seasonally, 16.7% of the spring samples and 28.4% of the autumn samples were positive. Based on molecular identification, three species of two genera were identified viz. M. fulvum (n = 57), M. canis (n = 2) and zoophilic Trichophyton interdigitale (n = 1). As a specific goal in the study, differentiation of the species in Microsporum gypseum complex was established by measuring the mean length and width of macroconidia in some strains of M. gypseum, M. fulvum and M. incurvatum. Mean size for macroconidia length and width in three species showed that M. gypseum and M. incurvatum can morphologically be differentiated from M. fulvum but not from each other. M. fulvum was the most abundant species isolated from the soils of Ahvaz; however, to comprehensively specify the distribution pattern of geophilic dermatophytes in the soils of this city further investigations are needed. Identification based on micro-morphometric is not effective for species distinction in M. gypseum complex, while molecular procedures based on sequencing of certain DNA regions are the most reliable and applicable strategies for this purpose.

Proteolytic activity and cooperative hemolytic effect of dermatophytes with different species of bacteria

BACKGROUND AND PURPOSE

Globally, dermatophytes are the most common filamentous group of fungi causing cutaneous mycoses. Dermatophytes were shown to secrete a multitude of enzymes that play a role in their pathogenesis. There is limited data on co-hemolytic (CAMP-like) effect of different bacterial species on dermatophyte species. In this study, we sought to the evaluate exoenzyme activity and co-hemolytic effect of four bacteria on clinical dermatophytes isolated from patients in Shiraz, Iran.

MATERIALS AND METHODS

A total of 84 clinical dermatophyte species were isolated from patients suffering dermatophytosis and identified by conventional methods. Hemolytic activity was evaluated with Columbia 5% sheep blood agar. Proteolytic activity was determined by plate clearance assay method, using gelatin 8% agar. CAMP-like factor was evaluated with four bacteria, namely, S. areus, S.saprophyticus, S.pyogenes, and S.agalactiae. Fisher's exact test was run for statistical analysis.

RESULTS

T. mentagrophytes was the most predominant agent (27 [32.1%]) followed by T. verrucosum(20 [23.8%]), T. tonsurans (10 [11.9%]), Microsporum canis (7 [8.3%]), T. rubrum (6 [7.1%]), E. floccosum (6 [7.1%]), M. gypseum (5 [6%]), and T. violaceum (3[3.6%]). The most common clinical area of dermatophytosis was the skin. All the isolates expressed the zone of incomplete alpha hemolysis. All the isolates had CAMP- positive reaction with S. aureus and the other bacteria were CAMP-negative. All the isolates expressed proteolytic activity and no significant differences were noted among diverse genera of dermatophytes and severities of proteolytic activity.

CONCLUSION

This study indicated that hemolysin and proteolytic enzymes potentially play a role in dermatophyte pathogenesis and S. aureus could be considered as a main bacterium for creation of co-hemolytic effect in association with dermatophyte species.

The Changing Face of Dermatophytic Infections Worldwide

Dermatophytes evolve along with the geography and socioeconomic conditions. Epidermophyton floccosum, Microsporum audouinii and Trichophyton schoenleinii acted as the major pathogens of superficial fungal diseases 100 years ago, but their frequency decreased dramatically since the middle of the twentieth century and they are limited to some less-developed countries nowadays; meanwhile, frequency of Trichophyton rubrum, Trichophyton interdigitale, Trichophyton tonsurans and Microsporum canis increased gradually, and these fungi have become the major species globally. Some other dermatophytes, i.e., Trichophyton violaceum, Trichophyton verrucosum and Microsporum ferrugineum, are mainly endemic in some parts of Africa, Asia and Europe. At present, T. rubrum is the leading pathogen for skin and nail fungal infections, whereas M. canis, T. tonsurans and T. violaceum present as the predominant dermatophytes involved in tinea capitis. Population mobility, changes in human lifestyle and advents of antifungal drugs will continually drive the dermatophyte evolution in the skin microenvironment. Comprehensive observation is needed to better understand this kind of organisms and prospect the trends of their changes in future.

Epidemiological survey of dermatophytosis in Damascus, Syria, from 2008 to 2016

Background and Purpose:

It is important to follow annually the probable changes in distribution pattern of dermatophytosis and its etiological agents in different communities. In this study, we determined the prevalence of dermatophytosis and its causative agents in Damascus, Syria, between 2008 and 2016.

Materials and Methods:

A total of 4080 outpatients who visited the dermatological clinics in Damascus, were evaluated. The specimens were collected from clinically suspected tinea. The patients were referred to our laboratory for direct examination by 30 %KOH. Some of the specimens were cultured on Sabouraud Dextrose Agar for fungal identification.

Results:

Out of the 4080 cases, 1138 cases were positive in direct examination(%27.89) , including Tinea pedis (%46.98), followed by tinea capitis(%39.79) , tinea corporis (%25.38), toenail onychomycosi (%20.33), tinea manuum (%16.06), and fingernail onychomycosis .(%15.22) Tinea pedis and toenail onychomycosis were more common in summer %41.19) and %25.78 respectively .(Trichophytic rubrum was the most prevalent fungal pathogen, especially in toenail onychomycosis.

Conclusion:

Dermatophytosis is highly prevalent in Syria. This study provides valuable data for differential diagnosis of dermatophytosis.

Epidemiological trends of dermatophytosis in Tehran, Iran: A five-year retrospective study

OBJECTIVE

Dermatophytosis is the most frequent fungal infection all over the world and its frequency is constantly increasing. The aim of this study was to evaluate clinical features and epidemiological trends of dermatophytosis over the years 2010 to 2014 in Tehran, Iran.

PATIENTS AND METHODS

A total of 13,312 patients clinically suspected of cutaneous fungal infections were examined. Skin scales, plucked hairs, nail clippings and sub-ungual debris were examined by direct microscopy and culture. Dermatophyte species were identified at the species level by a combination of morphological and physiological criteria.

RESULTS

Direct microscopy confirmed a contamination rate of 19.7% (2622/13,312 cases) of which 1535 cases (58.5%) were culture positive distributed in male (1022 cases) and female (513 cases). The most commonly infected age group was the 30-39 years old. Tinea pedis (30.4%) was the most prevalent type of dermatophytosis followed by tinea cruris (29.8%) and tinea corporis (15.8%). Epidermophyton floccosum (31%) was the most prevalent causative agent, followed by Trichophyton rubrum (26.2%) and Trichophyton mentagrophytes (20.3%).

CONCLUSION

Our results showed considerable distribution of dermatophytosis from zoophilic, anthropophilic and geophilic species among population with diverse age groups. Although anthropophilic fungi such as T. mentagrophytes, E. floccosum, and T. rubrum were the main etiologic agents of dermatophytosis, the prevalence of T. verrucosum showed a meaningful increase over the years, which highlights the importance of rural dermatophytosis mainly transmitted from large animals. This noticeable information improves our current knowledge about dermatophytosis and assists to establish effective prevention and therapeutic strategies to overcome the disease.

Development of a high-resolution melting analysis assay for rapid and high-throughput identification of clinically important dermatophyte species

Accurate identification of dermatophyte species is important both for epidemiological studies and for implementing antifungal treatment strategies. Although nucleic acid amplification-based assays have several advantages over conventional mycological methods, a major disadvantage is their high cost. The aim of this study was to develop a rapid and accurate real-time PCR-based high-resolution melting (HRM) assay for differentiation of the most common dermatophyte species. The oligonucleotide primers were designed to amplify highly conserved regions of the dermatophyte ribosomal DNA. Analysis of a panel containing potentially interfering fungi demonstrated no cross reactivity with the assay. To evaluate the performance characteristics of the method, a total of 250 clinical isolates were tested in comparison with the long-established PCR-RFLP method and the results were reassessed using DNA sequencing, as the reference standard method. The assay is able to type dermatophytes using normalised melting peak, difference plot analysis or electrophoresis on agarose gel methods. The results showed that, in comparison to PCR-RFLP, the developed HRM assay was able to differentiate at least 10 common dermatophytes species with a higher speed, throughput and accuracy. These results indicate that the HRM assay will be a useful sensitive, high throughput and cost-effective method for differentiating the most common dermatophyte species.

Epidemiological Aspects of Dermatophytosis in Khuzestan, southwestern Iran, an Update

Dermatophytosis is among the most common superficial mycoses in Iran. The purpose of this report was to update the clinical and mycological features of human dermatophytosis in the Khuzestan, southwestern Iran. In the framework of a one-year survey, a total of 4120 skin, hair and nail samples obtained from the outpatients with symptoms suggestive of tinea were analyzed by using direct microscopy, culture and molecular identification methods. Strains isolated from cultures were subjected to amplification of the nuclear rDNA ITS regions in a PCR assay followed by an early established RFLP analysis. For confirmation of species identification, 100 isolates as representatives of all presumable species were subjected to ITS sequencing. Infection was confirmed in 1123 individuals (27.25 %) in the age range of 1-89 years by direct microscopy and/or culture including 603 males versus 520 females. Frequencies of infections were the highest and the lowest in age groups of 21-30 and 11-20 years, respectively. Tinea corporis was the most prevalent clinical manifestation followed by tinea cruris, tinea capitis, tinea manuum, tinea pedis, tinea unguium, tinea faciei and tinea barbae. Trichophyton interdigitale (58.7 %) was the most dominant isolate followed by Epidermophyton floccosum (35.4 %), Microsporum canis (3 %), T. rubrum (1.5 %), T. species of Arthroderma benhamiae (0.5 %), T. tonsurans (0.3 %) and T. violaceum (0.3 %). Other species included M. gypseum, M. fulvum and T. verrucosum (each one 0.1 %). Such a high occurrence of infection with T. interdigitale, which has not been reported from Iran, is due to the use of accurate molecular methods based on new species concept in dermatophytes. The prevalence of dermatophytoses caused by zoophilic species remarkably increased and Trichophyton species of A. benhamiae has emerged as a new agent of dermatophytosis in southwestern Iran, while infections due to anthropophilic species, except E. floccosum, took a decreasing trend.

Phylogenetic analysis of dermatophyte species using DNA sequence polymorphism in calmodulin gene

Use of phylogenetic species concepts based on rDNA internal transcribe spacer (ITS) regions have improved the taxonomy of dermatophyte species; however, confirmation and refinement using other genes are needed. Since the calmodulin gene has not been systematically used in dermatophyte taxonomy, we evaluated its intra- and interspecies sequence variation as well as its application in identification, phylogenetic analysis, and taxonomy of 202 strains of 29 dermatophyte species. A set of primers was designed and optimized to amplify the target followed by bilateral sequencing. Using pairwise nucleotide comparisons, a mean similarity of 81% was observed among 29 dermatophyte species, with inter-species diversity ranging from 0 to 200 nucleotides (nt). Intraspecies nt differences were found within strains of Trichophyton interdigitale, Arthroderma simii, T. rubrum and A. vanbreuseghemii, while T. tonsurans, T. violaceum, Epidermophyton floccosum, Microsporum canis, M. audouinii, M. cookei, M. racemosum, M. gypseum, T. mentagrophytes, T schoenleinii, and A. benhamiae were conserved. Strains of E. floccosum/M. racemosum/M. cookei, A. obtosum/A. gertleri, T. tonsurans/T. equinum and a genotype of T. interdigitale had identical calmodulin sequences. For the majority of the species, tree topology obtained for calmodulin gene showed a congruence with coding and non-coding regions including ITS, BT2, and Tef-1α. Compared with the phylogenetic tree derived from ITS, BT2, and Tef-1α genes, some species such as E. floccosum and A. gertleri took relatively remote positions. Here, characterization and obtained dendrogram of calmodulin gene on a broad range of dermatophyte species provide a basis for further discovery of relationships between species. Studies of other loci are necessary to confirm the results.

A study on etiologic agents and clinical manifestations of dermatophytosis in Yazd, Iran

BACKGROUND AND PURPOSE

Dermatophytosis is one of the most common infections of skin, hair, and nails, caused by a group of keratinophilic fungi known as dermatophytes. Species identification of these fungi is of great significance from epidemiological and therapeutic points of view. The objective of the present study was to investigate dermatophytosis and its causative agents in patients, referring to the Central Mycology Laboratory of Yazd University of Medical Sciences, Yazd, Iran.

MATERIALS AND METHODS

In total, 139 clinically suspected cases of dermatophytosis were examined during 12 months from February 2014 to February 2015. Skin scrapings were assessed through direct microscopic examinations and culture studies. Dermatophyte isolates were identified based on colony morphology on potato dextrose agar and dermatophyte test medium, nutritional requirements, urease and hair perforation tests, and microscopic characteristics on slide cultures.

RESULTS

Dermatophytosis was mycologically confirmed in 26 (18.70%) out of 139 cases. Although there was a statistically insignificant difference between male and female subjects, men were dominantly affected. Infection was significantly common in the age group of ≤ 29 years (P<0.043). The most common clinical manifestation of dermatophytosis was tinea corporis (69.2%), followed by tinea cruris (15.4%), tinea manuum (11.5%), and tinea pedis (3.8%). Trichophyton mentagrophytes complex was the main etiologic agent (38.5%), followed by T. rubrum (23%), T. violaceum (15.5%), T. verrucosum (11.5%), Microsporum canis (7.7%), and Epidermophyton floccosum (3.8%).

CONCLUSION

In comparison with previous research, epidemiology of dermatophytosis has changed in Yazd over the past decades. Therefore, periodical investigations on the epidemiological aspects of this infection are required for efficient control and prevention of this cutaneous dermatophytic disease.

Molecular Characterization and In Vitro Antifungal Susceptibility of 316 Clinical Isolates of Dermatophytes in Iran

Dermatophytosis is a common mycotic infection of the skin, nail, and hair, associated with major public health concern worldwide. Various species of dermatophytes show significant differences in susceptibility to antifungals. Here, we present the antifungal susceptibility of a large collection of molecularly identified dermatophyte isolates obtained from tropical region of south of Iran. A total of 9485 patients clinically suspected to have cutaneous fungal infections were examined. Dermatophytosis was confirmed in 1502 cases by direct microscopy and culture. Three hundred and sixteen isolates recovered in culture were identified to species level using PCR sequencing of ITS region and RFLP. Tinea corporis was the most prevalent type of clinical manifestation (35.2 %), followed by tinea cruris (17 %), tinea capitis (12.8 %), tinea pedis (11.3 %), tinea manuum (11 %), tinea unguium (6.9 %), and tinea barbae (5.8 %). Trichophyton interdigitale was the most common isolate (49.36 %), followed by Trichophyton rubrum (18.98 %), Epidermophyton floccosum (13.29 %), Microsporum canis (9.17 %), Arthroderma benhamiae (T. anamorph of A. benhamiae; 5.38 %), and Trichophyton tonsurans (3.79 %). Overall, irrespective of the geographical region, terbinafine was the most potent antifungal against all isolates, with an MIC range of 0.002-0.25 μg/mL, followed by itraconazole (0.004-0.5 μg/mL), griseofulvin (0.125-8 μg/mL), and fluconazole (4-128 μg/mL). Analysis of our data revealed a significant increase in the frequency of A.benhamiae, which definitely warrants further investigation to explore source of this infection in south of Iran. Moreover, terbinafine was the most effective antifungal against all isolates, in vitro.

Use of Restriction Fragment Length Polymorphism to Rapidly Identify Dermatophyte Species Related to Dermatophytosis

BACKGROUND

Dermatophytes are a group of keratinophilic fungi worldwide, which can infect the skin, hair and nails of humans and animals. This genus includes several species that present different features of dermatophytosis. Although, laboratory diagnosis of dermatophytes is based on direct microscopy, biochemical tests and culture, these manners are expensive, time consuming and need skilled staff. Therefore, molecular methods like PCR-RFLP are the beneficial tools for identification, which are rapid and sensitive. Thus, dermatophyte species are able to generate characteristic band patterns on agarose gel electrophoresis using PCR-RFLP technique, which leads to successful identification at the species level within a 5-hour period.

OBJECTIVES

The purpose of this study was to study inter- and intraspecific genomic variations for identification of clinically important dermatophyte species obtained from clinical specimens in Isfahan, Iran using PCR-RFLP.

MATERIALS AND METHODS

From March 2011 to August 2012, 135 clinical isolates were collected from infected patients at Isfahan, Iran. ITS1-5.8S-ITS2 region of rDNA was amplified using universal fungal primers. Subsequently, amplified products were digested by the MvaI restriction enzyme. Using discriminating band profiles on agarose gel, dermatophyte species were identified. However, DNA sequencing was used for unidentifiable strains.

RESULTS

The specimens were obtained from skin scrapings (70.3%), nail (24.4%) and hair (5.1%) clippings. Most patients were between 21 - 30 years and the ratio of male to female was 93/42. Trichophyton interdigitale was the commonest isolate (52.5%) in our findings, followed by Epidermophyton floccosum (24.4%), T. rubrum (16.2%), Microsporum canis (2.2%), T. erinacei (1.4%), T. violaceum (1.4%), T. tonsurans (0.7%) and M. gypseum (0.7%) based on PCR-RFLP.

CONCLUSIONS

Combination of traditional methods and molecular techniques considerably improves identification of dermatophytes in the species level in clinical laboratories, which can lead to properly antifungal therapy and successful management of infections. However, restriction and specificity and sensitivity should be lowered and increased, respectively, to be useful for a wide variety of clinical applications.

The Efficacy of Ultraviolet Irradiation on Trichophyton Species Isolated From Nails

Background:

The treatment of onychomycosis is a challenge and infections are typically more severe and difficult to treat in toenails than in fingernails.

Objectives:

The current study aimed to investigate the fungicidal effect of ultraviolet radiation on the growth of dermatophytes isolated from nails.

Patients and Methods:

Samples from patients with clinical manifestations of onychomycosis were inoculated onto Sabouraud dextrose agar and incubated at 30°C for 14 days. Isolated species were identified by specific laboratory examinations; UV-A, UV-B, and UV-C light were used to irradiate two strains of Trichophyton mentagrophytes and T. rubrum. Colony count, size and growth rate of the isolated fungi were evaluated under laboratory conditions.

Results:

Trichophyton rubrum type 1 was less sensitive to UV-A and UV-C, and more sensitive to UV-B than type 2. T. mentagrophytes type 2 was slightly responsive to UV-A therapy, although no decrease in colony count was observed. Increased doses of UV-B and UV-C irradiation decreased the counts. The effect of radiation on colony size was dependent on the dose and type of irradiation.

Conclusions:

UV-A, UV-B, and UV-C light seem to be effective in decreasing colony growth of the most prevalent fungi, which caused onychomycosis in the current study samples. Further studies are needed to determine the efficacy of ultraviolet light therapy, identify possible side effects, and establish appropriate dosages for the antifungal effect of this therapy.

A 10-Year Study of Dermatophytoses in Isfahan, Iran

Dermatophyte infections are very common worldwide and their epidemiological characteristics vary according to the geographical region and have altered in the last decades. The aim of the present investigation was to determine the diversity of causative agents of dermatophytoses and describe the epidemiological condition of infection in Isfahan, Iran, between 2003 and 2012. Specimens were collected from hair, nail, and skin and were examined by conventional methods such as direct microscopy, culture on sabouraud dextrose agar with chloramphenicol and cycloheximide (Mycosel agar) and sabouraud glucose agar, Trichophyton agars, growth on rice grains, urease test, and hair perforation test. Of 13,469 clinically suspected cases, 11.5% were affected with dermatophytoses. Tinea capitis was the most frequent form of infection (52.7%), followed by tinea corporis (24%), tinea pedis (8.9%). Trichophyton verrucosum was the most prevalent causative agent (40.6%), followed by T. mentagrophytes var. interdigitale (17.6%), Epidermophyton floccosum (13%), T. violaceum (12%), T. rubrum (4.1%). Age range of patients was between 1 and 80 years. Housewives were the most patients in our study. The study emphasizes importance of epidemiological surveys of dermatophyte species for the better management of infection.

A comparative study on morphological versus molecular identification of dermatophyte isolates

OBJECTIVE

Dermatophytes are taxonomically classified in the genera Trichophyton, Microsporum, and Epidermophyton. Pleomorphism, cultural variability, slow growth and sporulation, and the need for additional physiological tests make dermatophytes notoriously difficult to identify. The present study aimed to compare the results of morphological and molecular identification of certain groups of clinical isolates of dermatophytes with a view to evaluating the accuracy of molecular methods.

PATIENTS AND METHODS

For each sample, the ITS1-5.8S-ITS2 rDNA region was amplified using the primers ITS1 and ITS4. PCR products were subjected to restriction fragment length polymorphism (RFLP) analysis using the enzyme MvaI and isolate identification was performed by comparing the electrophoretic RFLP patterns with reference profiles obtained previously. Finally, paired comparative analyses of molecular and conventional methods were performed.

RESULTS

While morphology results from routine daily reports of the laboratories indicated that 18 (6.8%) and 136 (52.10%) of the isolates were T. rubrum and T. interdigitale, respectively, PCR-RFLP results suggested that T. rubrum was the most common etiological agent of ringworm accounting for 94 (36.01%), followed by T. interdigitale accounting for 71 (27.20%). Interestingly, 80.8% out of the 94 isolates identified as T. rubrum by molecular testing had been identified by morphological examination as belonging to different species, such as T. interdigitale (75.5%), E. floccosum (2.1%) and M. canis, T. verrucosum, and T. tonsurans (each 1.06%). Ten strains out of 261 (T. interdigitale, n=8; E. floccosum, n=2) had been defined as unknown species by morphological tests.

CONCLUSION

An unexpected high percent of isolates identified as T. interdigitale by conventional methods were in effect T. rubrum shown by PCR-RFLP, and regarding the necessity of correct identification of dermatophytes recovered from different clinical forms of the infection, we highly recommend ITS-sequencing or ITS-RFLP of the isolates, particularly for epidemiological research studies.