Ulcerative Unilateral Tinea Manuum Caused by Nannizzia gypsea.

Dermatophytes, fungi specialized in keratin degradation, are key agents in skin infections, commonly referred to as tineas. Tinea manuum, affecting the hands, typically presents in noninflammatory or inflammatory forms, with ulcerative manifestations rarely reported. Nannizzia gypsea, a relatively uncommon cause of tineas, exhibits variable prevalence influenced by geographic factors. This study investigates a case of Ulcerative Unilateral Tinea Manuum caused by N. gypsea, aiming to explore the differential diagnosis, pathogenesis, and management. A 23-year-old female from the Yucatan Peninsula presented with an ulcerated lesion on her left hand. Initially suspected as Leishmaniasis, subsequent examination revealed tinea manuum. The study discusses differential diagnoses, highlighting the rarity of ulcerative presentations in dermatophytosis, and explores potential pathogenic mechanisms. This case underscores the importance of considering dermatophytes in ulcerative skin lesions and suggests a comprehensive diagnostic approach, particularly in endemic regions.

An update on antifungal resistance in dermatophytosis.

INTRODUCTION: The reports of resistance to antifungal agents used for treating onychomycosis and other superficial fungal infections are increasing. This rise in antifungal resistance poses a public health challenge that requires attention. AREAS COVERED: This review explores the prevalence of dermatophytes and the current relationship between dermatophyte species, their minimum inhibitory concentrations (MICs) for terbinafine (an allylamine) and itraconazole (an azole), and various mutations prevalent in these species. The most frequently isolated dermatophyte associated with resistance in patients with onychomycosis and dermatophytosis was T. mentagrophytes. However, T. indotineae emerged as the most prevalent isolate with mutations in the SQLE gene, exhibiting the highest MIC of 8 µg/ml for terbinafine and MICs of 8 µg/ml and ≥ 32 µg/ml for itraconazole.Overall, the most prevalent SQLE mutations were Phe397Leu, Leu393Phe, Ala448Thr, Phe397Leu/Ala448Thr, and Lys276Asn/Leu415Phe (relatively recent). EXPERT OPINION: Managing dermatophyte infections requires a personalized approach. A detailed history should be obtained including details of travel, home and occupational exposure, and clinical examination of the skin, nails and other body systems. Relevant testing includes mycological examination (traditional and molecular). Additional testing, where available, includes MIC evaluation and detection of SQLE mutations. In case of suspected terbinafine resistance, itraconazole or voriconazole (less commonly) should be considered.

Potential Sexual Transmission of Antifungal-Resistant Trichophyton indotineae.

We describe a case of tinea genitalis in an immunocompetent woman in Pennsylvania, USA. Infection was caused by Trichophyton indotineae potentially acquired through sexual contact. The fungus was resistant to terbinafine (first-line antifungal) but improved with itraconazole. Clinicians should be aware of T. indotineae as a potential cause of antifungal-resistant genital lesions.

Terbinafine resistance in Trichophyton mentagrophytes and Trichophyton rubrum in the Czech Republic: A prospective multicentric study.

BACKGROUND: Terbinafine, an allylamine antifungal, is crucial for treating dermatophytosis by inhibiting squalene epoxidase (SQLE) in the ergosterol biosynthetic pathway. However, resistance is emerging, particularly in India and Southeast Asia, but reports of resistance spread worldwide. Despite this, comprehensive studies on terbinafine resistance in Trichophyton are still limited. OBJECTIVES: This research aimed to determine the prevalence of terbinafine resistance in the Czech Republic, with a focus on Trichophyton rubrum and Trichophyton mentagrophytes, and investigate the underlying molecular mechanisms. PATIENTS/METHODS: A total of 514 clinical strains of T. rubrum and 240 T. mentagrophytes collected from four Czech clinical institutions were screened for terbinafine resistance. Molecular investigations included DNA sequencing, specifically the ITS rDNA region and SQLE gene, as well as antifungal susceptibility testing following EUCAST guidelines. RESULTS: While no resistance was observed in T. rubrum, 2.5% of T. mentagrophytes strains exhibited resistance, marked by the F397L mutation in SQLE. Notably, resistance surged from 1.2% in 2019 to 9.3% in 2020 but reverted to 0% in 2021. All resistant strains were identified as T. mentagrophytes var. indotineae. Resistant strains exhibited high MICs for terbinafine (≥4 mg L-1 ) but low MICs to the other seven antifungals tested except for fluconazole. CONCLUSIONS: This study highlights the emergence of terbinafine-resistant T. mentagrophytes strains in the Czech Republic, with the F397L mutation being pivotal. Due to the relatively low resistance level, the current guidelines for dermatomycosis treatment in the Czech Republic remain effective, but ongoing surveillance is essential for timely adaptations if resistance patterns change.

Evaluation of the antidermatophytic activity of potassium salts of N-acylhydrazinecarbodithioates and their aminotriazole-thione derivatives.

Nowadays, dermatophyte infections are relatively easy to cure, especially since the introduction of orally administered antifungals such as terbinafine and itraconazole. However, these drugs may cause side effects due to liver damage or their interactions with other therapeutics. Hence, the search for new effective chemotherapeutics showing antidermatophyte activity seems to be the urge of the moment. Potassium salts of N-acylhydrazinecarbodithioates are used commonly as precursors for the synthesis of biologically active compounds. Keeping that in mind, the activity of a series of five potassium N-acylhydrazinecarbodithioates (1a-e) and their aminotriazole-thione derivatives (2a-e) was evaluated against a set of pathogenic, keratinolytic fungi, such as Trichophyton ssp., Microsporum ssp. and Chrysosporium keratinophilum, but also against some Gram-positive and Gram-negative bacteria. All tested compounds were found non-toxic for L-929 and HeLa cells, with the IC30 and IC50 values assessed in the MTT assay above 128 mg/L. The compound 5-amino-3-(naphtalene-1-yl)-4,5-dihydro-1H-1,2,4-triazole-5-thione (2d) was found active against all fungal strains tested. Scanning Electron Microscopy (SEM) revealed inhibition of mycelium development of Trichophyton rubrum cultivated on nail fragments and treated with 2d 24 h after infection with fungal spores. Transmission Electron Microscopy (TEM) observation of mycelium treated with 2d showed ultrastructural changes in the morphology of germinated spores. Finally, the RNA-seq analysis indicated that a broad spectrum of genes responded to stress induced by the 2d compound. In conclusion, the results confirm the potential of N-acylhydrazinecarbodithioate derivatives for future use as promising leads for new antidermatophyte agents development.

Exploring the Complexity of the Interaction between T. rubrum and S. aureus/S. epidermidis in the Formation of Polymicrobial Biofilms.

Dermatophytes associated with bacteria can lead to severe, difficult-to-treat infections and contribute to chronic infections. Trichophyton rubrum, Staphylococcus aureus, and Staphylococcus epidermidis can form biofilms influenced by nutrient availability. This study investigated biofilm formation by these species by utilizing diverse culture media and different time points. These biofilms were studied through scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), biomass, metabolic activity, and colony-forming units (CFUs). The results revealed that mixed biofilms exhibited high biomass and metabolic activity when cultivated in the brain heart infusion (BHI) medium. Both bacterial species formed mature biofilms with T. rubrum within 72 h, irrespective of media. The timing of bacterial inoculation was pivotal in influencing biomass and metabolic activity. T. rubrum's development within mixed biofilms depended on bacterial addition timing, while pre-adhesion influenced fungal growth. Bacterial communities prevailed initially, while fungi dominated later in the mixed biofilms. CLSM revealed 363 µm thick T. rubrum biofilms with septate, well-developed hyphae; S. aureus (177 µm) and S. epidermidis (178 µm) biofilms showed primarily cocci. Mixed biofilms matched T. rubrum's thickness when associated with S. epidermidis (369 µm), with few hyphae initially. Understanding T. rubrum and Staphylococcal interactions in biofilms advances antimicrobial resistance and disease progression knowledge.

Molecular Verification of Trichophyton in the Brazilian URM Culture Collection.

Trichophyton species cause dermatophytosis in humans, with a high, worldwide frequency of reports and important public health relevance. We evaluated 61 Trichophyton strains from different sources deposited in the University Recife Mycology (URM) culture collection of the Universidade Federal de Pernambuco, Brazil. Strains were phenotypically identified and confirmed by sequencing Internal Transcribed Spacers rDNA and partial beta-tubulin 2-exon. Additionally, we evaluated their susceptibility to terbinafine and itraconazole. Physiological analyses included urease activity and growth in casein medium. Phenotypic methods allowed the reliable identification of T. rubrum only, whereas, for other species, molecular methods were mandatory. All Trichophyton species exhibited susceptibility profiles to itraconazole (0.04-5.33 µg/mL) and terbinafine (0.17-3.33 µg/mL). Our analyses revealed a heterogeneous distribution of T. mentagrophytes, which does not support the current distribution within the species complex of T. mentagrophytes and its genotypes.

Treatment of onychomycosis in an era of antifungal resistance: Role for antifungal stewardship and topical antifungal agents.

A growing body of literature has marked the emergence and spread of antifungal resistance among species of Trichophyton, the most prevalent cause of toenail and fingernail onychomycosis in the United States and Europe. We review published data on rates of oral antifungal resistance among Trichophyton species; causes of antifungal resistance and methods to counteract it; and in vitro data on the role of topical antifungals in the treatment of onychomycosis. Antifungal resistance among species of Trichophyton against terbinafine and itraconazole-the two most common oral treatments for onychomycosis and other superficial fungal infections caused by dermatophytes-has been detected around the globe. Fungal adaptations, patient characteristics (e.g., immunocompromised status; drug-drug interactions), and empirical diagnostic and treatment patterns may contribute to reduced antifungal efficacy and the development of antifungal resistance. Antifungal stewardship efforts aim to ensure proper antifungal use to limit antifungal resistance and improve clinical outcomes. In the treatment of onychomycosis, critical aspects of antifungal stewardship include proper identification of the fungal infection prior to initiation of treatment and improvements in physician and patient education. Topical ciclopirox, efinaconazole and tavaborole, delivered either alone or in combination with oral antifungals, have demonstrated efficacy in vitro against susceptible and/or resistant isolates of Trichophyton species, with low potential for development of antifungal resistance. Additional real-world long-term data are needed to monitor global rates of antifungal resistance and assess the efficacy of oral and topical antifungals, alone or in combination, in counteracting antifungal resistance in the treatment of onychomycosis.

Microbes on Clipper Blades after Use and Disinfection in Small Animal- and Equine Practice.

Clipping hair on animals can produce microtraumas of the skin and the dislodgement of microorganisms to the clipper blade. This study evaluates if clipper blades in animal hospitals in Sweden are contaminated with bacteria and/or dermatophytes after disinfection. Eleven clipper blades from three veterinary referral hospitals, including one with a small animal department and an equine department, were sampled for bacteria and dermatophytes. All the hospitals had disinfection routines in accordance with the national recommendations for hygiene in veterinary medicine. The sampled clipper blades were supposed to be disinfected and they were considered to be ready for use by staff. Five sterilized clipper blades were used as controls. The results showed that 64-100% of the disinfected clipper blades, from all three hospitals, were contaminated with bacteria, whereas all the sterilized clipper blades were negative for bacterial growth (p < 0.05). One clipper blade from the equine department was contaminated with dermatophytes. The results indicate that the disinfection routines were not sufficient for removing bacteria from used clipper blades, and that sterilization would be a more reliable way to minimize the risk of contamination.

Case Report: Diagnosing Dermatophytoses in Children.

Dermatophytoses of the skin and scalp are common disorders in the pediatric population. The resemblance of the clinical presentation to other dermatoses can make fungal infections challenging to diagnose. We present three cases of dermatophytoses in children. The presence of fungi within skin lesions was confirmed in all cases. The diagnoses were "id" reaction in response to Trichophyton tonsurans infection, Kerion celsi because of Microsporum canis infection, and hair loss during microsporosis. Based on our review and clinical experience, we suggest diagnostic paths and treatments for dermatophytoses in children.

Dermatophytosis is uncommon in asymptomatic wild eastern cottontail rabbits in Illinois, Midwestern United States.

OBJECTIVE: To investigate the presence of dermatophytes on the haircoat of wild eastern cottontail rabbits (ECR) (Sylvilagus floridanus) with and without skin lesions. ANIMALS: 2-week-old or older ECR admitted to a Wildlife Medical Clinic (WMC) in central Illinois, Midwest United States, from September 2021 to August 2022. METHODS: ECR were surveyed over a 1-year period to assess the prevalence and seasonality of dermatophytosis. A Wood's lamp exam was performed over the haircoat. Hairs were sampled with a sterile toothbrush and plated on Sabouraud dextrose agar. The plates were photographed twice weekly for 3 weeks, and colonies were identified as contaminants or dermatophytes. RESULTS: 523 ECR were admitted to WMC, 141 ECR met the age inclusion criteria, and 121 samples were plated. ECR presented as a litter were sampled together. None of the sampled ECR presented skin lesions other than acute traumatic wounds. No fluorescence was observed on any ECR during the Wood's lamp examination. Based on culture colony morphology, 115/121 of the samples were identified as contaminants and no growth was observed in 6/121 of plates. Dermatophytes' colonies were not identified on any of the culture plates. CLINICAL RELEVANCE: Dermatophytes are zoonotic fungi and can potentially be carried by wild animals. The fungal infection poses a health concern to humans and domestic pets through direct interaction. Our current results suggest that dermatophytosis may not be prevalent in asymptomatic wild rabbits in the studied areas of the Midwestern United States.

PCR-based methods in detection and identification of dermatophytes in dogs and cats with suspected dermatophytosis in 2021 in Poland.

Dermatophytes from Microsporum, Trichophyton and Epidermophyton genera are divided into geophilic, zoophilic and anthropophilic species which cause skin infection in humans and wide group of animals, mainly mammals. Main species causing dermatophytosis in dogs and cats are Microsporum and Trichophyton. Conventional mycological diagnostic technique includes Saburaud Dextrose Agar (SAD) and others medium cultures, 10% KOH mount and direct microscopy of hairs and scraping. Molecular diagnostic become more frequent in veterinary practice due to shortening of waiting time. In this study we based on two PCR methods. The nested PCR amplified CHS1 gene for dermatophytes detection, and multiplex PCR coding ITS1 and ITS2 fragments for species identification of detected derpatophytes. Most frequently detected species was Microsporum canis, mainly in young cats. Geophilic Microsporum gypseum and anthropophilic Trichophyton rubrum was found primarily in dogs. Molecular methods in dermatophytosis identification are rapid in contrast to routinely, long lasting culture.

Azorean Black Tea (Camellia sinensis) Antidermatophytic and Fungicidal Properties.

The treatment of dermatophytoses, the most common human fungal infections, requires new alternatives. The aim of this study was to determine the antidermatophytic activity of the aqueous Azorean Black Tea extract (ABT), together with an approach to the mechanisms of action. The phytochemical analysis of ABT extract was performed by HPLC. The dermatophytes susceptibility was assessed using a broth microdilution assay; potential synergies with terbinafine and griseofulvin were evaluated by the checkerboard assay. The mechanism of action was appraised by the quantification of the fungal cell wall chitin and ß-1,3-glucan, and by membrane ergosterol. The presence of ultrastructural modifications was studied by Transmission Electron Microscopy (TEM). The ABT extract contained organic and phenolic acids, flavonoids, theaflavins and alkaloids. It showed an antidermatophytic effect, with MIC values of 250 µg/mL for Trichophyton mentagrophytes, 125 µg/mL for Trichophyton rubrum and 500 µg/mL for Microsporum canis; at these concentrations, the extract was fungicidal. An additive effect of ABT in association to terbinafine on these three dermatophytes was observed. The ABT extract caused a significant reduction in ß-1,3-glucan content, indicating the synthesis of this cell wall component as a possible target. The present study identifies the antidermatophytic activity of the ABT and highlights its potential to improve the effectiveness of conventional topical treatment currently used for the management of skin or mucosal fungal infections.

Clinico-Mycological Study of Onychomycosis in Indian Diabetic Patients.

Background: Onychomycosis (OM) is the most common nail disorder accounting for 40-50% of all onychopathies. Onychomycosis is caused by dermatophytes in majority, mostly Trichophyton (T.) rubrum followed by T. mentragrophytes var. interdigitale. However, there is a variation in the etiological profile with the subset of population, time, and geographical location. In immunocompromised hosts, non-dermatophytic molds (NDMs) and yeasts like Candida albicans and Candida parapsilosis are the main causative agents. Diabetes mellitus (DM) is a well-established risk factor for OM. Aim and Objectives: This study was conducted to determine the clinical and mycological characteristics of OM in diabetic patients and to evaluate the clinico-etiological correlation, if any. Materials and Methods: Three hundred consecutive diabetic patients were screened, of whom 102 (34%) patients were diagnosed with OM based on clinical, mycological, dermoscopic, and histological criteria. Results: Distal lateral subungual onychomycosis was the most common clinical variant seen in 80 (78.43%) patients. Fungal culture was positive in 57 (55.88%) of which NDMs constituted approximately half (47.61%) of the isolates, followed by Candida species (30.15%) and dermatophytes (22.22%). The clinico-mycological correlation was performed to look for the association of various fungi with the clinical type of OM. Distal lateral subungual onychomycosis was majorly caused by NDMs (51.02%), followed by Candida species (28.57%), and dermatophytes (20.40%). Conclusion: Non-dermatophytic molds are increasingly incriminated as the causative organisms for OM in DM and must be considered as potential pathogens in the present scenario, thus necessitating the change in the treatment options accordingly.

Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database.

BACKGROUND: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. AIMS: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). METHODS: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. RESULTS: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%. CONCLUSIONS: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.

Rapid and Accurate Diagnosis of Dermatophyte Infections Using the DendrisCHIP® Technology.

Dermatophytosis is a superficial fungal infection with an ever-increasing number of patients. Culture-based mycology remains the most commonly used diagnosis, but it takes around four weeks to identify the causative agent. Therefore, routine clinical laboratories need rapid, high throughput, and accurate species-specific analytical methods for diagnosis and therapeutic management. Based on these requirements, we investigated the feasibility of DendrisCHIP® technology as an innovative molecular diagnostic method for the identification of a subset of 13 pathogens potentially responsible for dermatophytosis infections in clinical samples. This technology is based on DNA microarray, which potentially enables the detection and discrimination of several germs in a single sample. A major originality of DendrisCHIP® technology is the use of a decision algorithm for probability presence or absence of pathogens based on machine learning methods. In this study, the diagnosis of dermatophyte infection was carried out on more than 284 isolates by conventional microbial culture and DendrisCHIP®DP, which correspond to the DendrisCHIP® carrying oligoprobes of the targeted pathogens implicated in dermatophytosis. While convergence ranging from 75 to 86% depending on the sampling procedure was obtained with both methods, the DendrisCHIP®DP proved to identify more isolates with pathogens that escaped the culture method. These results were confirmed at 86% by a third method, which was either a specific RT-PCR or genome sequencing. In addition, diagnostic results with DendrisCHIP®DP can be obtained within a day. This faster and more accurate identification of fungal pathogens with DendrisCHIP®DP enables the clinician to quickly and successfully implement appropriate antifungal treatment to prevent the spread and elimination of dermatophyte infection. Taken together, these results demonstrate that this technology is a very promising method for routine diagnosis of dermatophytosis.

Survey of Sensitization to Common Fungi in an Allergic Dog Population: The Need for Further Focus on Sensitization and Allergy to Fungi in Veterinary Medicine.

Most fungal species are commensals and non-pathogenic to plants, humans, or animals. However, several species of the Alternaria, Aspergillus, Trichophyton, and Microsporum genera are common causes of disease, even for immunocompetent individuals. Besides mucosal damage, fungi may contribute to a skin barrier impairment, favoring sensitization and allergy development. A total of 68 allergic dogs were selected from a veterinary dermatology and allergy outpatient consultation for conditions related to both Malassezia overgrowth and other fungal complications. The allergy diagnosis was made through anamnesis and current clinical criteria, with the involved allergenic species being identified by intradermal tests (IDTs) and allergen-specific immunoglobulin E (sIgE) determination in serum. Dermatophagoides farinae, Dactylis glomerata, and Malassezia pachydermatis showed as the higher sensitization species from house dust mites, grass pollen, and fungi, respectively. Significant correlations at p < 0.05 were found between sensitization to Dactylis glomerata and Phleum pratense grass pollens, Dermatophagoides farinae and Dermatophagoides pteronyssinus, Acarus siro, Tyrophagus putrescentiae, and Lepidoglyphus destructor dust/storage mites, and between fungi like Aspergillus mix and Penicillium or Alternaria alternata. A significant correlation was also found between sensitization to the Aspergillus mix and D. farinae, D. pteronyssinus, or A. siro. Rather severe dermatitis was observed when a positive IDT to Malassezia pachydermatis was found, regardless of the detection of circulating sIgE, allowing us to consider the usefulness of both the IDT and the sIgE for a systematic diagnosis of allergy to fungi.

Effect of the 1064 nm Nd: YAG Laser on the MICs of Antifungals Used in Clinical Practice for the Treatment of Fungal Nail Infections.

Introduction: The fungal nail infection (onychomycosis) involves 18%-40% of all nail disorders, which, although not fatal, can cause mechanical, aesthetic, occupational, and economic problems. Drug treatments due to prolonged treatment periods, drug interactions, adverse effects, and slow progression may associate with numerous negative outcomes. This study aimed to evaluate the long-pulsed 1064-nm Nd: YAG laser effect on fungal colonies and subsequently possible change in the minimum inhibitory concentrations (MICs) of common antifungals compared with the same non-lasered colonies as a novel way to investigate laser and antifungal interaction. Methods: Sixty onychomycosis samples consisting of saprophyte (n=20), dermatophyte (n=20), and yeast (n=20) duplicate colonies were isolated. A series was treated by a long-pulsed 1064-nm Nd: YAG laser. Afterward, the MIC (CLSI-M38-A2 and CLSI-M27-A3) of two series against common antifungals were compared. Results: After 1064-nm Nd: YAG laser irradiation in all 20 tested saprophytes, the MICs of terbinafine (P value<0.035) were changed, and in all 20 tested dermatophytes, the MICs of voriconazole (P value<0.021) were changed. Also, in all 20 tested yeasts, the MICs of caspofungin (P value<0.037) were changed. Moreover, in saprophytes, dermatophytes, and yeasts, significant changes in the MICs of itraconazole (P value<0.032), terbinafine (P value<0.025), and caspofungin (P value<0.037) were detected. Our result showed the GM MICs of the 1064-nm Nd: YAG laser in all saprophyte, dermatophyte, and yeast groups were lower than in the control group. Conclusion: The present study indicated that the long-pulsed 1064-nm Nd: YAG laser significantly changes the MICs of antifungals in onychomycosis clinical samples.

Two different types of tandem sequences mediate the overexpression of TinCYP51B in azole-resistant Trichophyton indotineae.

Trichophyton indotineae is an emerging dermatophyte that causes severe tinea corporis and tinea cruris. Numerous cases of terbinafine- and azole-recalcitrant T. indotineae-related dermatophytosis have been observed in India over the past decade, and cases are now being recorded worldwide. Whole genome sequencing of three azole-resistant strains revealed a variable number of repeats of a 2,404 base pair (bp) sequence encoding TinCYP51B in tandem specifically at the CYP51B locus position. However, many other resistant strains (itraconazole MIC ≥0.25 µg/mL; voriconazole MIC ≥0.25 µg/mL) did not contain such duplications. Whole-genome sequencing of three of these strains revealed a variable number of 7,374 bp tandem repeat blocks harboring TinCYP51B. Consequently, two types of T. indotineae azole-resistant strains were found to host TinCYP51B in tandem sequences (type I with 2,404 bp TinCYP51B blocks and type II with 7,374 bp TinCYP51B blocks). Using the CRISPR/Cas9 genome-editing tool, the copy number of TinCYP51B within the genome of types I and II strains was brought back to a single copy. The azole susceptibility of these modified strains was similar to that of strains without TinCYP51B duplication, showing that azole resistance in T. indotineae strains is mediated by one of two types of TinCYP51B amplification. Type II strains were prevalent among 32 resistant strains analyzed using a rapid and reliable PCR test.