Trichophyton Interdigitale Research Articles

Epidemiological study of antifungal-resistant dermatophytes isolated from Japanese patients.

An epidemiological study of antifungal drug-resistant dermatophytes was conducted as a follow-up to our 2020 survey. Dermatophytes were isolated in 2022 from the same dermatology clinics as in the previous study. In total, 288 Trichophyton interdigitale and Trichophyton rubrum clinical isolates were obtained from 288 human cases of dermatophytosis in Tokyo, Saitama, Shizuoka, and Kumamoto, Japan. Four strains were found to be resistant to terbinafine (TRF) and susceptible to itraconazole (ITZ), luliconazole (LCZ), and ravuconazole (RVZ), and three other strains were found to be resistant to ITZ and susceptible to TRF, LCZ, and RVZ. We determined the sequences of the squalene epoxidase (SQLE)-encoding gene in the three TRF-resistant T. rubrum strains, and found that two strains harbored L393F missense mutations, and one strain harbored a F397L missense mutation. The results of the present study indicated that the prevalence of TRF-resistant dermatophytes has not increased since 2020. However, TRF-resistant T. interdigitale (L393F mutation) was isolated for the first time, indicating that attention should be paid to the presence of TRF-resistant T. interdigitale in the future. We also examined for the first time the epidemiology of ITZ-resistant T. rubrum in Japanese patients. Although the number of ITZ-resistant strains was not large, the results confirmed that ITZ-resistant T. rubrum strains do exist in Japanese patients.

Treatment recalcitrant cases of tinea corporis/cruris causedby T. mentagrophytes - interdigitale complex with mutations in ERG11 ERG 3, ERG4, MDR1 MFS genes & SQLE and their potential implications.

Recalcitrant dermatophyte infections are being reported from various parts of the world due to varied causes including strain variation, steroid misuse, SQLE mutations, and variable quality of itraconazole pellet formulations. The oral drug preferred in endemic areas is itraconazole, to which MIC levels remain low, and clinical failures to itraconazole reported defy a sound scientific explanation. The objective of the study was to conduct a proteomic and genomic analysis on isolates from therapeutically recalcitrant case with isolation of gene mutations and enzymatic abnormalities to explain azole failures. Trichophyton mentagrophyte interdigitale complex strains were isolated from seven clinically non-responding tinea corporis/cruris patients, who had failed a sequential course of 6 weeks of terbinafine 250 mg QD and itraconazole 100 mg BID. After AFST 1 strain, KA01 with high MIC to most drugs was characterized using whole genome sequencing, comparative proteomic profiling, and total sterol quantification. Sterol quantification showed that the standard strain of Trichophyton mentagrophytes (MTCC-7687) had half the ergosterol content than the resistant KA01 strain. Genomic analysis revealed mutations in SQLE, ERG4, ERG11, MDR1, MFS genes, and a novel ERG3 mutation. Proteomic analysis established the aberrant expression of acetyl Co-A transferase in the resistant strain and upregulation of thioredoxin reductase and peroxiredoxin. Our findings demonstrate possible reasons for multidrug resistance in the prevalent strain with mutations in genes that predict terbinafine (SQLE) and azole actions (ERG4, ERG11, ERG3) apart from efflux pumps (MDR1, MFS) that can explain multidrug clinical failures.

Synthesis of vanillin derivatives with 1,2,3‐triazole fragments and evaluation of their fungicide and fungistatic activities

Vanillin is the main component of natural vanilla extract and is responsible for its flavoring properties. Besides its well-known applications as an additive in food and cosmetics, it has also been reported that vanillin can inhibit fungi of clinical interest, such as Candida spp., Cryptococcus spp., Aspergillus spp., as well as dermatophytes. Thus, the present work approaches the synthesis of a series of vanillin derivatives with 1,2,3-triazole fragments and the evaluation of their antifungal activities against Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, Cryptococcus neoformans, Cryptococcus gattii, Trichophyton rubrum, and Trichophyton interdigitale strains. Twenty-two vanillin derivatives were obtained, with yields in the range of 60%-91%, from copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction between two terminal alkynes prepared from vanillin and different benzyl azides. In general, the evaluated compounds showed moderate activity against the microorganisms tested, with minimum inhibitory concentration (MIC) values ranging from 32 to >512 µg mL-1 . Except for compound 3b against the C. gattii R265 strain, all vanillin derivatives showed fungicidal activity for the yeasts tested. The predicted physicochemical and ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties for the compounds indicated favorable profiles for drug development. In addition, a four-dimensional structure-activity relationship (4D-SAR) analysis was carried out and provided useful insights concerning the structures of the compounds and their biological profile. Finally, molecular docking calculations showed that all compounds bind favorably at the lanosterol 14α-demethylase enzyme active site with binding energies ranging from -9.1 to -12.2 kcal/mol.

Comparison of in vitro activities of newer triazoles and classic antifungal agents against dermatophyte species isolated from Iranian University Hospitals: a multi-central study

BackgroundDermatophytes have the ability to invade the keratin layer of humans and cause infections. The aims of this study were the accurate identification of dermatophytes by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism method and sequencing and comparison between the in vitro activities of newer and established antifungal agents against them.MethodsClinical specimens of patients from five Iranian university laboratories were entered in this study. Samples were cultured on sabouraud dextrose agar medium. For molecular identification, extracted DNAs were amplified by the universal fungal primers ITS1 and ITS4, and digested with MvaI enzymes. The antifungal susceptibility test for each isolate to terbinafine, griseofulvin, caspofungin, fluconazole, itraconazole, luliconazole, and isavuconazole was performed, according to the microdilution CLSI M38-A2 and CLSI M61 standard methods.ResultsTwo hundred and seven fungi species similar to dermatophytes were isolated of which 198 (95.6%) were dermatophytes by molecular assay. The most commonly isolated were Trichophyton mentagrophytes (76/198), followed by Trichophyton interdigitale (57/198), Trichophyton rubrum (34/198), Trichophyton tonsurans (12/198), Microsporum canis (10/198), Trichophyton simii (3/198), Epidermophyton floccosum (3/198), Trichophyton violaceum (2/198), and Trichophyton benhamiae (1/198). The GM MIC and MIC90 values for all the isolates were as follows: terbinafine (0.091 and 1 μg/ml), griseofulvin (1.01 and 4 μg/ml), caspofungin (0.06 and 4 μg/ml), fluconazole (16.52 and 32 μg/ml), itraconazole (0.861 and 8 μg/ml), isavuconazole (0.074 and 2 μg/ml), and luliconazole (0.018 and 0.25 μg/ml).ConclusionTrichophyton mentagrophytes, Trichophyton interdigitale, and Trichophyton rubrum were the most common fungal species isolated from the patients. luliconazole, terbinafine, and isavuconazole in vitro were revealed to be the most effective antifungal agents against all dermatophyte isolates.

Evaluation of the heat sensitivity of Trichophyton rubrum and Trichophyton interdigitale.

Onychomycosis affects up to 50% of patients in the older population. This study aimed to explore heat sensitivity of Trichophyton rubrum and Trichophyton interdigitale as pathogens of onychomycosis. The fungi were heated in sterile saline solution up to 100°C for five or 10 minutes with or without additional previous treatment with 1% ciclopirox solution or chitinase and 1,3 -galactidase or for 45 minutes at 40°C or 60°C with washing powder. Subsequently, the fungi were cultured and regrowth was assessed after one week. After heating T. rubrum for five minutes at 60°C, growth was completely inhibited. After heating T. interdigitale for five minutes at 60°C, all of the samples regrew, and at 95°C, none of the samples regrew. No difference between five and 10-minute heating was observed. Previous incubation with 1% ciclopirox solution for 24hours inhibited the growth of T. rubrum completely. T. interdigitale was still able to regrow to 100% after five minutes at 40°C, to 33% after 60°C, and to 22% after 80°C. Incubation for 45 minutes with washing powder solution at 40°C or 60°C did not lead to significant growth reduction of T. rubrum or interdigitale. Two hours incubation with -1,3-glucanase and chitinase prior to five minutes of heating to 60°C and 80°C reduced the heat resistance of T. interdigitale; growth was inhibited in 56% and 100% of the samples, respectively. The heat resistance of T. rubrum and interdigitale should be considered using non-medical thermal treatment.

Evaluation of a Liquid Media MALDI-TOF MS Protocol for the Identification of Dermatophytes Isolated from Tinea capitis Infections.

One of the most common types of tinea is the superficial infection of the hair and scalp area known as tinea capitis. It is responsible for frequent outbreaks in nurseries and schools and represents a global health problem. Correct identification of the infection agent is essential in the determination of the infection source, epidemiological course, and treatment initiation. The conventional identification methods (direct exam, culture, DNA sequencing) are time-consuming, require experienced staff, are time-consuming, and the latter is expensive for routine identifications. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is gaining new ground for routine identification of filamentous fungi. The main advantages of MALDI-TOF MS are its rapid and accurate identification capability, relatively low cost, and easy integration into the laboratory routine. Its accuracy heavily depends on the quality of the reference spectra database. Identification of clinical isolates with MALDI-TOF MS protocol requires a sub-culturing step to ensure reliable identification. It can take days to weeks before fungal growth appears on solid medium. In this study, a unique MALDI-TOF MS protocol using liquid cultures of dermatophyte species was developed in order to shorten the turnaround time for the culture and identification of clinical isolates. Material and Method A standard MALDI-TOF MS protocol was adapted for liquid instead of solid cultures. Three different databases were tested. Results Using the liquid media MALDI-TOF MS protocol, a global rate of 62% correct identification (RCI) was obtained, compared with 87% for the protocol based on solid cultures. Trichophyton tonsurans was not correctly identified in all isolates using liquid cultures, with 88% of the isolates misidentified as Trichophyton interdigitale. The turnaround time for primary isolates for the solid and liquid protocols were respectively 11.7 and 11.6 days (no significant difference between both methods (p = 0.96)). Conclusions The newly designed liquid MALDI-TOF MS protocol did not lead to a significantly shorter turnaround time for the identification of dermatophytes isolated from tinea capitis infections. The turnaround time for the method with primary isolates was not significantly lower, and the rate of correct identification decreased remarkably, which emphasizes the need for a sub-culturing step. Using different database did not lead to improvement in turnaround time or rate of correct identification. This study highlights the importance of the medium and the reference database when performing MALDI-TOF MS.

Exposure to itraconazole influences the susceptibility to antifungals, physiology, and virulence of Trichophyton interdigitale.

Dermatophytosis is the most common human skin infection worldwide caused by dermatophytes, such as Trichophyton interdigitale and Trichophyton rubrum. Itraconazole (ITZ) is one of the main antifungals used to treat these infections. However, especially for onychomycosis, the treatment requires long-term regimens, increasing the possibility of drug resistance. We evaluated the effects of ITZ in the physiology, virulence, and interaction of T. interdigitale with phagocytes and mice cutaneous infection. In a screening test, fungal growth in the presence of ITZ led to the spontaneous selection of less susceptible T. interdigitale and T. rubrum strains. Interestingly, this phenotype was permanent for some T. interdigitale strains. Then, we studied three T. interdigitale strains: one susceptible and two ITZ-adapted. The ITZ-adapted strains were also less susceptible to the cell wall and membrane stressors, suggesting a multidrug resistance (MDR) phenotype associated with the increased ERG11 and MDR3 expression. These strains also presented substantial alterations in ergosterol content, lipid peroxidation, biofilm, and extracellular matrix production. During interaction with macrophages, ITZ-adapted strains were less engulfed but increased the intracellular oxidative and nitrosative bursts. In addition, ITZ-adapted strains presented a reduced ability to grow in a murine model of dermatophytosis, although causing the same tissue damage as the parental strain. In conclusion, the T. interdigitale ITZ adaptation increases tolerance to antifungals and alters the interaction with macrophages and a mammalian host. We hypothesized that successive exposure to ITZ may influence the emergence of adapted strains and lead to the recalcitrance of dermatophytosis.

P505 Genotyping of Trichophyton mentagrophytes infections in animals in Italy through sequencing of the ITS region

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMObjectives Trichophyton mentagrophytes is a zoophilic dermatophyte that recognizes lagomorphs and rodents as primary hosts. The fungus can also infect other animals, such as dogs and cats. While T. mentagrophytes is a polymorphic sexual species, T. interdigitale is recognized as its clonal offshoot. This delineation is meaningful from a clinical point of view in human patients. Trichophyton interdigitale is exclusively anthropophilic and mainly causes non-inflammatory chronic tinea pedis or onychomycosis. Trichophyton mentagrophytes is predominantly of animal origin and often leads to the development of inflammatory lesions. These two dermatophytes form a species complex and have several ribosomal internal transcribed spacer (ITS) region genotypes. Identifying the ITS type allows species attribution and simultaneously strain typing. Many studies have been dedicated to this argument concerning human infections, while scarce information is available regarding animals. This study aimed to gain insights into the current epidemiology of T. mentagrophytes genotypes in animals.MethodsThe fungal isolates included in the study regarded cases involving various animal species seen at multiple veterinary clinics in Italy (n = 39) and France (n = 1) between 2005 and 2021. DNA was extracted from isolates cultured on Sabouraud dextrose agar using a commercially available kit (NucleoSpin® Tissue, Macherey-Nagel, Düren, Germany). PCR was performed with the primer pair V9G and LR3. PCR products were sequenced using ITS5 and ITS4 primers through a commercial service (Macrogen Europe). Using MEGA11 software (https://www.megasoftware.net/), ITS sequences were aligned with the currently recognized genotypes (6 and 22 for T. interdigitale and T. mentagrophytes, respectively).ResultsFigure 1 shows the ITS Type attribution for our isolates within a phylogenetic tree that includes the currently recognized genotypes. A new genotype (that, following the nomenclature, we called XXVII) was found in two isolates coming from a dog and a cat living in the same city. Figure 2 shows the distribution of the genotypes according to the animal host.A total of 23 samples out of 40 (57.5%) belonged to the ITS Type III*. It was the lone found in rabbits and the most prevalent in cats. This finding agrees with past literature, which reported a wide distribution of this ITS type in European animals. Of note is the high number of isolates with ITS Type II* found in dogs. ITS Type II* differs only by one nucleotide substitution from T. interdigitale and is considered an ‘intermediate’ entity between it and T. mentagrophytes. Clinical pictures, as well as molecular data, would suggest attributing this genotype to T. interdigitale. On the other hand, it has been detected from animal sources (chinchilla, guinea pig, and brown rat) which would justify its interpretation as T. mentagrophytes. Our data support the latter possibility.Though we could not have a detailed description of all the dogs harboring ITS Type II*, it is noteworthy that many showed the same clinical presentation, i.e., exfoliative chronic disseminated alopecia. Moreover, in most cases, despite the extensive lesions, the infection was not transmitted to the owners.ConclusionsThis study adds information on the molecular epidemiology of T. mentagrophytes infections in animals.

P100 Potent inhibition of dermatophyte fungi by Australian native jarrah honey

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM ObjectivesHoney has been used as a remedy for multiple ailments, and the antibacterial activity of many different floral honeys has been extensively explored. The capacity of honey to inhibit fungi is much less well understood. Here we investigate the inhibition of dermatophyte species by native Australian jarrah honey.MethodsJarrah honey was sourced from beekeepers and commercial suppliers. Artificial honey, made from glucose (22.9%), fructose (20.7%), and sucrose (1.6%), was used to control for osmolarity. Hydrogen peroxide production by honey was assessed using horseradish peroxidase (HRP)/ο‐dianisidine colorimetric test. Dermatophytes included Microsporum canis, M. nanum, Nannizzia gypsea, Trichophyton interdigitale, T. rubrum, and T. tonsurans. Minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) for honey were assessed using CLSI methods. Fluorescent and scanning electron microscopy were used to visualize the effect of honey on fungal conidia and hyphae.ResultsJarrah honey inhibited all of the dermatophyte species with MICs ranging from 1.5-3.5% w/v, and MFCs from 2-5% w/v. No antifungal activity was seen with the artificial honey indicating this was not due to osmolarity. Microscopy revealed honey treatment prevented the germination of conidia and caused hyphae to bulge and collapse. While the inhibitory action of jarrah honey was greatly reduced by the addition of catalase suggesting hydrogen peroxide production was responsible for inhibition and killing, microscopy revealed hyphae were still damaged suggesting there are agents within honey that augment antifungal activity. REDOX fluorophores failed to detect internal oxidative stress within hyphae, indicating that damage likely occurs on the hyphal surface.ConclusionJarrah honey is a non-toxic agent that may have utility in the treatment of superficial fungal infections caused by dermatophyte fungal species.

P475 Bee health and the antifungal activity of honey

Poster session 1, September 21, 2022, 12:30 PM - 1:30 PM ObjectivesVarious components have been identified which contribute to the antimicrobial properties of honey, many of which are secreted by bees into the honey as it is being processed. Here we investigate the relationship between bee and hive health and the antifungal properties of honey.MethodsSamples of honey were collected from hives that were either healthy or experiencing some kind of distress as assessed by beekeepers. Healthy hives displayed strong population numbers and good brood patterns while distressed hives exhibited warning signs such as low population numbers, patchy brood patterns, evidence of chalkbrood fungal disease, or small hive beetle infestation. Honey samples were tested for antifungal activity against yeast and mold species via broth microdilution, tested for hydrogen peroxide levels via colorimetric assay, and spread on agar plates to assess the abundance and diversity of microbes present in the raw honey.ResultsHoney samples were effective against the yeast Cryptococcus deuterogattii and the dermatophyte mold Trichophyton interdigitale but ineffective against the yeast Candida dubliniensis and the mold Aspergillus flavus. The hydrogen peroxide levels of the honeys were variable and did not always align with activity. Less microbes in number and abundance were present on agar plates grown from healthy hive honey compared to distressed hive honey.ConclusionThese results indicate that bee health may play a role in contributing to the antifungal properties of honey and that promoting strong and healthy hives is beneficial.

Submission and Phylogenetical of Local Isolated Trichophyton interdigitale of Iraqi Patients in NCBI

Dermatophytes are species with slight genetic variation, and are yet several uncertainties about the differences among species. This study aims to isolate and diagnose the Trichophyton interdigitale by molecular technique and to reveal the phylogenetic distance and similarity of the Iraqi isolates to other isolates from the globe, in addition, to submit the obtained sequences to the NCBI database. This study included 86 with multiple lesions on different parts of the body. The results showed different variations within the ITS gene between the isolates. It was concluded that Trichophyton interdigitale in Iraqi isolates had two types of substitution variations (Transition and Transversion) different than global isolates. Moreover, it appeared according to the phylogenetic tree, the similarity was 97% with isolates from the Czech Republic and Japan, whereas 98% with the isolates from France and Germany. Keywords. Dermatophytes, genetic variations, ITS gene, multiple lessons

Reactive oxygen and nitrogen species are crucial for the antifungal activity of amorolfine and ciclopirox olamine against the dermatophyte Trichophyton interdigitale.

Onychomycosis is a nail infection, which can be treated with amorolfine and ciclopirox olamine. Here we demonstrate that these drugs exhibit antifungal activity also through the production of oxidative and nitrosative radicals.

Applicability of Dermoscopy in the Atypical Presentation of Tinea Pedis: A Case Report

Tinea pedis, also known as athlete’s foot or foot ringworm is an infection of the feet or toes with dermatophyte fungus [1]. Trichophyton rubrum is the most common isolate accounting for 70% of cases. Other species include Trichophyton interdigitale, Trichophyton mentagrophytes and Epidermophyton floccosum. The ideal conditions for fungal growth include hot and humid environment, prolonged use of occlusive footwear, excessive sweating and prolonged exposure to water [2]. The maceration of the skin due to above risk factors along with keratinases released by fungus helps in easy invasion of the keratin layer. The mannans contained in the fungal cell wall also further suppress the body’s immunity thus, contributing to tinea pedis. Herein we describe a case of recurrent vesiculobullous type of tinea pedis who was inappropriately managed previously.

Antimicrobial Activities of Salacia oblonga Wall Leaf and Root Extracts Against Different Bacterial Strains and Fungal Isolates.

Antibiotic resistance and the hazardous nature of synthetic drugs is threatening issue in the health sector. The alternative for this problem is to focus on plants that attribute to various compounds that exhibit therapeutic properties. Therefore, the study aims to evaluate the antimicrobial efficacy of Salacia oblonga leaf and root extracts against tested human pathogens. The S. oblonga extracts showed a significant zone of inhibition against bacteria and fungi. The leaf and root extracts of S. oblonga are prepared using low polar to high polar solvents in the Soxhlet apparatus and tested on the selected bacterial and fungal strains. Agar well diffusion and broth dilution methods evaluate antibacterial activity, antifungal activity, and Minimum Inhibitory Concentration (MIC) of extracts. Among the extracts tested, the ethyl acetate extract of root showed more antimicrobial activity against the tested bacterial and fungal strains. The most susceptible bacterial and fungal species against ethyl acetate extract are Micrococcus luteus, Mycobacterium tuberculosis, Microsporum canis, Trichophyton interdigitale, and Microsporum gypseum. The MIC for bacteria ranged from 13.0 to > 200µg/ml, whereas for fungi, the MIC ranged from 25.9 to > 200µg/ml. Ethyl acetate extract of root with 100µg/ml concentration showed 29.1mm and 28.7mm zone of inhibition against bacterial strains M. luteus and M. tuberculosis, respectively. The ethyl acetate extract of root with a 100µg/ml concentration showed 15.8, 15.2, and 15.6mm zone of inhibition against fungal isolates M. canis, T. interdigitale, and M. gypseum, respectively. The activity of root and leaf extracts increased in a concentration-dependent manner, and further, the compounds isolated from the crude extracts of leaf and root showed antimicrobial activity. Structural elucidation of isolated compounds Lambertic acid and Ferruginol was done using NMR spectroscopy. Reports indicate that Lambertic acid was isolated previously, but the isolation of hydroxy Ferruginol from S. oblonga leaf extract was reported unprecedented.

First Report of the Biosynthesis and Characterization of Silver Nanoparticles Using Scabiosa atropurpurea subsp. maritima Fruit Extracts and Their Antioxidant, Antimicrobial and Cytotoxic Properties.

Candida and dermatophyte infections are difficult to treat due to increasing antifungal drugs resistance such as fluconazole, as well as the emergence of multi-resistance in clinical bacteria. Here, we first synthesized silver nanoparticles using aqueous fruit extracts from Scabiosa atropurpurea subsp. maritima (L.). The characterization of the AgNPs by means of UV, XRD, FTIR, and TEM showed that the AgNPs had a uniform spherical shape with average sizes of 40–50 nm. The biosynthesized AgNPs showed high antioxidant activity when investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The AgNPs displayed strong antibacterial potential expressed by the maximum zone inhibition and the lowest MIC and MBC values. The AgNPs revealed a significant antifungal effect against the growth and biofilm of Candida species. In fact, the AgNPs were efficient against Trichophyton rubrum, Trichophyton interdigitale, and Microsporum canis. The antifungal mechanisms of action of the AgNPs seem to be due to the disruption of membrane integrity and a reduction in virulence factors (biofilm and hyphae formation and a reduction in germination). Finally, the silver nanoparticles also showed important cytotoxic activity against the human multiple myeloma U266 cell line and the human breast cancer cell line MDA-MB-231. Therefore, we describe new silver nanoparticles with promising biomedical application in the development of novel antimicrobial and anticancer agents.

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

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

Non-Dermatophyte Mold Dominated Onychomycosis in Patients Attending a Rank Higher Specialized Dermatology Clinic in Addis Ababa, Ethiopia.

BackgroundOnychomycosis is a common refractory fungal infection associated with significant morbidity. The objective of this study was to determine the prevalence of onychomycosis, and the diversity and species composition of fungal etiological agents.Materials and MethodsA clinic-based, prospective, non-randomized cross-sectional study was carried out between October 2018 and June 2019 at Rank Higher Specialized Dermatology Clinic, Addis Ababa, Ethiopia. Nail scrapings were collected aseptically from 200 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.ResultsAmong 200 nail scrapings, 161 (80.5%) samples were found out to be culture positive. Of these, 135 (83.9%) samples yielded single colonies while 26 (16.1%) mixed colonies gave a total of 190 isolates. Among the isolates, 25.8% were dermatophytes while 61.1% were non- dermatophytes molds, and 13.1% were yeasts. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant species.ConclusionThe prevalence rate of onychomycosis in the present study was high. The isolation rate of non-dermatophyte molds was higher than dermatophytes and yeasts. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant etiological agents. Females and patients in the middle age group were more affected. An increase in the prevalence of non-dermatophyte molds in nail infections dictates further investigation demonstrating how this group of fungi causes onychomycosis.

Azolo[5,1‐c][1,2,4]triazines and Azoloazapurines: Synthesis, Antimicrobial activity and in silico Studies

AbstractThe present work reports on the synthesis of series of azolo[5,1‐c][1,2,4]triazines and derivatives of azoloazapurines. The synthesized compounds were tested in vitro for antibacterial activity against N. gonorrhoeae and antimycotic activity against Trichophyton interdigitale, Epidermophyton floccosum, Microsporum canis and Candida albicans. It was found that 10 compounds of the series of 3‐nitroazolo[5,1‐c][1,2,4]triazine‐4‐amines 4 exhibit high antibacterial activity (MIC≤15 μg/ml), but do not exhibit antimycotic activity. For compounds active against N. gonorrhoeae, a biological target was predicted from the pharmacophore search method and homologous modeling was carried out for it. The results of molecular docking using the constructed model of dihydrofolate reductase have a good correlation with in vitro tests. Refined docking showed the similarity of the leading compounds positions in the protein active site. The formation of stable non‐covalent bonds of the nitro group with the amino acid residues Lys34/Lys55 makes a major contribution to the orienting effect of ligands.

Comment on: Multicentre validation of a EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes

In 2020, we published a multicentre study validating a new EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes.1 We included molecularly confirmed terbinafine-resistant and -susceptible Trichophyton rubrum and Trichophyton interdigitale isolates and established wild-type upper MIC limits (WT-UL) for both species. Since then, the taxonomy for the Trichophyton mentagrophytes/T. interdigitale complex has been revised and a new species Trichophyton indotineae proposed for the highly terbinafine-resistant Indian isolates.2,3 These species cannot be distinguished by phenotypic tests although T. indotineae isolates are most often lighter in colour and less often positive in Tween-80 opacity, urea hydrolysis and hair perforation tests than T. mentagrophytes and T. interdigitale.3 Consequently, T. indotineae has been reported in the literature under all three species names and susceptibility data reported for the species complex cannot be reliably linked to the individual species unless identification to the sensu stricto level has...

Real‐life applicability of the Euroarray dermatomycosis kit in the diagnosis of onychomycosis

Traditionally, KOH microscopy and fungal culture are the two preferred tests as gold standard for diagnosis of onychomycosis. Recently, other diagnostic methods have been developed to improve the microbiological diagnosis. The EUROArray dermatomycosis kit is a PCR-based microarray test system for the detection and direct identification of species that are most frequently involved in skin and nail infections. Our primary aim was to evaluate the real-life applicability of the EUROArray dermatomycosis kit in the diagnosis of onychomycoses. In addition, we compared the aetiology of onychomycoses found in our patients with those described in the literature. We prospectively studied consecutive 100 patients with suspected onychomycoses. Samples of suspect toenails were taken as part of routine medical management. Nail specimens were evaluated by means of three diagnostic methods: KOH preparation, culture and EUROArray dermatomycosis kit. Onychomycosis was diagnosed in 47/100 patients who proved positive on at least one reference diagnostic test and in 49/100 patients who proved positive on PCR. The combination of microscopy and PCR had better sensitivity than microscopy (p=.0397), fungal culture (p=.0061) and PCR alone (p=.0117). Moulds were more frequently positive in culture than in PCR (p=.033). Dermatophytes proved positive more frequent than moulds and yeasts in both culture and PCR; in particular, Trichophytoninterdigitale was the most frequent pathogen. In conclusion, introducing EUROArray dermatomycosis kit into the diagnostic algorithm of onychomycosis increases the sensitivity of direct microscopy and yields more rapid results than culture.