Molecular Detection of Dermatophytes and Nondermatophytes in Onychomycosis in Antalya, Turkey.

BACKGROUND: Onychomycosis is a chronic nail infection, and dermatophytes, yeasts, and nondermatophytic molds may be the causative agents. This study aimed to determine the etiological agents of onychomycosis by using conventional and molecular methods. METHODS: Between June 2020 and July 2021, 37 patients with a presumptive diagnosis of onychomycosis and mycological evidence (culture and/or EUROArray Dermatomycosis assay) were included in the study. Organisms detected in cultured nail specimens were identified by combined phenotypic characteristics and by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). An EUROarray Dermatomycosis assay was used for molecular detection of fungal pathogens. RESULTS: The EUROArray Dermatomycosis assay was positive for a single fungal target in 23 samples, and 14 samples were positive by culture. The most common pathogen was Trichophyton rubrum in both methods. Coinfection was detected in 14 samples by using molecular methods, and Trichophyton rubrum and Fusarium solani (9 samples) were the most common pathogens detected together. Trichophyton spp., nondermatophyte molds, and Candida spp. were detected in 33 (89.2%), 16 (43.2%), and 6 (16.2%) samples, respectively, when the two methods were evaluated together. CONCLUSIONS: Our results revealed that fungal culture allows the diagnosis of onychomycosis, but it is not as sensitive as the EUROArray Dermatomycosis test, especially in patients receiving antifungal therapy.

A survey of 701 cases of tinea faciei in Hangzhou, southeastern China, from 2018 to 2023.

BACKGROUND: Tinea faciei, a specific dermatophytosis that affects the glabrous skin of the face, not only causes physical discomfort but also leads to greater psychological distress. Tinea faciei is a public health concern. OBJECTIVES: To analyse the epidemiological characteristics, responsible dermatophyte species and clinical features of tinea faciei in Hangzhou. METHODS: Data were obtained from the Laboratory Information System of the Mycology Laboratory and Medical Information System at a hospital in Hangzhou. Isolates were identified based on their macroscopic appearance and microscopic morphology. RESULTS: Tinea faciei was diagnosed in 701 patients, involving 359 males and 342 females, aged between 2 months and 97 years. In total, 499 isolates (71.18%) were identified as Trichophyton rubrum. Anthropophilic isolates were identified in 297 (82.73%) males and 207 (60.53%) females (p < .01). Among patients with anthropophilic dermatophytes infection, 447 (88.69%) were adults. Zoophilic dermatophytes were isolated in 57 (15.88%) males and 130 (38.01%) females (p < .01), among whom 108 (57.75%) were children. CONCLUSIONS: Anthropophilic dermatophytes, especially T. rubrum, were the predominant cause of tinea faciei, while zoophilic dermatophytes were the most prevalent in children. Compared with men, women may be more susceptible to zoophilic dermatophytes.

Tinea faciei clinical characteristics, causative agents, treatments and outcomes; a retrospective study in Thailand.

BACKGROUND: Tinea faciei is a relatively uncommon dermatophyte infection. The studies, which included clinical forms, and isolated species of dermatophytes, are limited. MATERIALS AND METHODS: This retrospective study aims to determine the causative organism, clinical characteristics, treatments and outcomes of patients with tinea faciei attending the dermatologic clinic, Siriraj Hospital, from 1 January 2017 to 30 September 2021. Demographic data, clinical presentations, isolated dermatophyte species, treatments and outcomes were collected and analysed. RESULTS: A total of 151 tinea faciei cases were observed. Trichophyton rubrum (48.6%), Trichophyton mentagrophytes complex (22.2%) and Microsporum canis (18.1%) were common causative agents. Tinea faciei was commonly detected in females (64.9%) with a history of pets (54.6%). Clinical presentations often involved plaques and scales on the cheeks. Among patients with lesions on the cheek, mycological cure was observed significantly less often compared to those without cheek lesions. Patients with other concurrent skin or nail infections, a history of topical steroids and a history of previous fungal infection had a slightly longer duration of mycological cure than those without factors. Recurrent infection was found in 33.3%. Male, history of previous fungal infection, and lesions on the cheeks were significantly associated with recurrent infection. CONCLUSIONS: Fungal infection of the face was commonly found in women and patients with pets. The most common pathogen that caused tinea faciei was T. rubrum. Topical antifungal treatments could be used with favourable outcomes. The history of past infection and lesion on the cheeks should be carefully assessed to be vigilant for recurrent infection.

Epidemiology of Tinea Capitis Among School-Children in Dschang, Western Cameroon.

Data on the epidemiology of tinea capitis (TC), an infection of the scalp by dermatophytes, are scarce in Cameroon. This study aimed to determine the prevalence of TC among school-children in the Dschang Subdivision, Western Cameroon. A cross-sectional study was carried out in June 2021 in Dschang including pupils aged 5-13. First, a standardized questionnaire was administered to participant for the collection of sociodemographic data. Then, samples were collected and cultured onto Sabouraud-Chloramphenicol-Gentamicin Agar. The etiological agents were identified based on their morphological features and with MALDI-TOF mass spectrometry. A total of 1070 children were clinically examined and 108 (10.1%) children presented with TC lesions. The mean age of the 1070 participants was 8.3 ± 2.6 years (range: 5-13 years); 772 (72.2%) were males. The use of borehole water (OR = 0.01, 95%CI[0.001-0.03]), spring water (OR = 0.2, 95%CI[0.08-0.50]), rainwater (OR = 0.004, 95%CI[0.001-0.016]), and hairdressing salons visits (OR = 0.413, 95%CI[0.196-0.872]) were associated with a decreased TC risk in the multivariate logistic regression analysis. In contrast, sharing bed with siblings (OR = 4.48, 95%CI[2.095-9.60]) was associated with an increased TC risk in children. Among the 32 dermatophytes isolated in culture, Microsporum audouinii was the most frequent (43.8%), followed by Trichophyton rubrum (25.0%) and T. soudanense (25.0%). Microsporum canis and T. violaceum were both rarely isolated. Further studies are warranted to assess the association of TC with domestic water usage that has been highlighted in this study.

Trichophyton indotineae and other terbinafine-resistant dermatophytes in North America.

Dermatophyte infections (a.k.a. ringworm, tinea) affect an estimated 20%-25% of the world's population. In North America, most dermatophytoses are caused by Trichophyton rubrum or Trichophyton mentagrophytes species complexes. Severe and antifungal-resistant dermatophytoses are a growing global public health problem. A new species of the T. mentagrophytes species complex, Trichophyton indotineae, has recently emerged and is notable for the severe infections it causes, its propensity for antifungal resistance, and its global spread. In this issue of the Journal of Clinical Microbiology, C. F. Cañete-Gibas, J. Mele, H. P. Patterson, et al. (J Clin Microbiol 61:e00562-23, 2023, https://doi.org/10.1128/JCM.00562-23) summarize the results of speciation and AFST performed on North American dermatophyte isolates received at a fungal diagnostic reference laboratory. Within their collection, 18.6% of isolates were resistant to terbinafine (a first-line oral antifungal for dermatophytoses), and similar proportions of T. rubrum and T. indotineae demonstrated terbinafine resistance. The authors also found that T. indotineae has been present in North America since at least 2017. These findings highlight the importance of increased surveillance efforts to monitor trends in severe and antifungal-resistant dermatophytoses and the need for antifungal stewardship efforts, the success of which is contingent upon improving laboratory capacity for dermatophyte speciation and AFST.

Immunity to commensal skin fungi promotes psoriasiform skin inflammation.

Under steady-state conditions, the immune system is poised to sense and respond to the microbiota. As such, immunity to the microbiota, including T cell responses, is expected to precede any inflammatory trigger. How this pool of preformed microbiota-specific T cells contributes to tissue pathologies remains unclear. Here, using an experimental model of psoriasis, we show that recall responses to commensal skin fungi can significantly aggravate tissue inflammation. Enhanced pathology caused by fungi preexposure depends on Th17 responses and neutrophil extracellular traps and recapitulates features of the transcriptional landscape of human lesional psoriatic skin. Together, our results propose that recall responses directed to skin fungi can directly promote skin inflammation and that exploration of tissue inflammation should be assessed in the context of recall responses to the microbiota.

Benzylpenicillin-producing Trichophyton erinacei and methicillin resistant Staphylococcus aureus carrying the mecC gene on European hedgehogs - A pilot-study.

BACKGROUND: A high carriage rate of methicillin-resistant Staphylococcus aureus with the mecC gene (mecC-MRSA) has been described among Wild European hedgehogs (Europeaus erineaus). Due to this frequent occurrence, it has been suggested that hedgehogs could be a natural reservoir for mecC-MRSA. However, the reason why hedgehogs carry mecC-MRSA remains unknown, but it has been hypothesized that mecC-MRSA could have evolved on the skin of hedgehogs due to the co-occurrence with antibiotic producing dermatophytes. The aim of this pilot-study was therefore to investigate if hedgehogs in Sweden carry Trichophyton spp. and to provide evidence that these dermatophytes are able to produce penicillin or similar substances. In addition, the study aimed to identify if dermatophytes co-occurred with mecC-MRSA. METHODS: Samples were collected from hedgehogs (Europeaus erineaus) that were euthanized or died of natural causes. All samples were screened for dermatophytes and mecC-MRSA using selective cultivation methods. Suspected isolates were characterized using PCR-based methods, genome sequencing and bioinformatic analyses. Identification of penicillin was performed by ultra-high-performance liquid chromatography-tandem mass spectrometry. RESULTS: In total 23 hedgehogs were investigated, and it was shown that two carried Trichophyton erinacei producing benzyl-penicillin, and that these hedgehogs also carried mecC-MRSA. The study also showed that 60% of the hedgehogs carried mecC-MRSA. CONCLUSION: The pilot-study demonstrated that Trichophyton erinacei, isolated from Swedish hedgehogs, can produce benzylpenicillin and that these benzylpenicillin-producing T. erinacei co-occurred with mecC-MRSA. The study also reconfirmed the high occurrence of mecC-MRSA among hedgehogs.

Efficacy and safety of topical terbinafine 10% solution (MOB-015) in the treatment of mild to moderate distal subungual onychomycosis: A randomized, multicenter, double-blind, vehicle-controlled phase 3 study.

BACKGROUND: Onychomycosis is a recalcitrant fungal nail infection. Topical antifungal agents may be preferred over systemic agents due to lack of systemic adverse effects. OBJECTIVE: To investigate the efficacy and safety of topical terbinafine 10% solution (MOB-015) for the treatment of distal and lateral subungual onychomycosis. METHODS: In a multicenter, double-blind, phase III, North American study, patients with mild to moderate distal and lateral subungual onychomycosis involving 20% to 60% of at least 1 great toenail were randomized to once daily application of MOB-015 or matching vehicle for 48 weeks. The primary efficacy variable was complete cure, while the secondary efficacy variables were mycological cure and treatment success. Safety evaluations were also performed. RESULTS: At week 52, the mycological cure (negative culture and potassium hydroxide microscopy) rate in the MOB-015 and vehicle groups was 69.9% and 27.7%, respectively (P < .001), and complete cure (0% clinical disease involvement and mycological cure) was achieved in 4.5% and 0% of patients, respectively (P = .0195). At least 1 adverse event leading to discontinuation of treatment occurred in 2.8% of patients in the MOB-015 group and in 4.2% in the vehicle group. LIMITATION: The follow-up period after end of treatment may not be sufficient to accurately reflect cure in distal and lateral subungual onychomycosis. CONCLUSIONS: MOB-015 is a treatment option for onychomycosis with an adverse event profile similar to vehicle.

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

AIMS: Accurate identification of dermatophytes is essential for implementing appropriate antifungal treatment and epidemiological analysis. However, the limitations of conventional diagnostics are a frequently discussed topic, and new diagnostic techniques are constantly expanding. In this study, we assess the suitability of conventional diagnostic techniques in comparison to the real-time PCR assay and MALDI-TOF MS in detection and identification of dermatophytes. METHODS AND RESULTS: Strains included in this study were obtained from human and animals with symptomatic, and asymptomatic infection. A direct examination revealed that 31·7 and 60·9% of samples from symptomatic patients, and 25·7 and 60% from asymptomatic animals were positive, as shown by light and fluorescence microscopy respectively. In turn, dermatophytes were isolated from 90·2 and 71·4% of these samples. The pan-dermatophyte primers in real-time PCR assay facilitated detection in 85·3 and 82·9% of the symptomatic and asymptomatic dermatophytoses respectively. Additionally, species-specific PCR assays were positive in 70·7 and 37·1% of these samples. The MALDI-TOF MS analysis yielded positive results consistent with conventional techniques in 97·2 and 72% of symptomatic and asymptomatic infections respectively. CONCLUSIONS: Our study revealed that there is no universal diagnostic method that would be ideal in each of the cases considered. Nonetheless, conventional techniques are still the most effective and reliable tools for mycological diagnostics. SIGNIFICANCE AND IMPACT OF THE STUDY: Dermatologists and veterinarians have difficulties in making a diagnosis of dermatophytoses based only on observed symptoms of fungal infections, as they mimic symptoms of other dermatoses. In this context, a comparative analysis of the results of diagnostics performed using conventional methods and new technologies are crucial for implementing these pioneer methods into routine laboratory practice.

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

AIMS: Keratin is a fibrous and recalcitrant structural protein and the third most abundant polymer in nature after cellulose and chitin. Subtilisin-like proteases (SUB) are a group of serine endoproteases, coded by seven genes (SUB1-7), which decompose keratin structures and have been isolated from dermatophytes. Herein, we identified the SUB genes in 30 clinical isolates of Trichophyton verrucosum obtained from human and animal dermatophytosis as well as asymptomatic animal carriers. METHODS AND RESULTS: We designed and proposed a two-stage multiplex PCR technique to detect all seven genes encoding serine proteases in dermatophytes. The analysis revealed the presence SUB1 and SUB2 amplicons in all strains regardless of the host. In the group of isolates obtained from humans, all seven subtilisin genes were shown in 40% of the strains. In T. verrucosum from asymptomatic animals, none of the isolates showed the presence of all seven subtilisin genes, and only 30% had six genes. In turn, 10% of the isolates from symptomatic animals demonstrated all seven subtilisins amplicons. CONCLUSIONS: In conclusion, the severity of infection and ability of T. verrucosum to cause dermatophytosis in humans may not be related to specific genes but their accumulation and synergistic effects of their products. SIGNIFICANCE AND IMPACT OF THE STUDY: Dermatophytes are pathogenic filamentous fungi with capacity to attack keratinized structures such as skin, hair and nails, causing cutaneous superficial infections. Indeed, a biological characteristic of dermatophytes is their ability to invade keratin-rich tissues by producing enzymes. Various degrees of inflammatory responses can be induced exactly by the enzymes. Subtilisin-like proteases are endoproteases, which decompose keratin structures. Our study identifies SUB genes in clinical isolates of T. verrucosum obtained from human and animal dermatophytosis as well as asymptomatic animal carriers.

Comprehensive genome and transcriptome analysis of the dermatophyte Trichophyton schoenleinii reveals the candidate pathogenic genes.

BACKGROUND: Trichophyton schoenleinii is an anthropophilic dermatophyte that causes tinea favosa. Nowadays, it remains an important pathogen in some regions of the world, mainly epidemic in Africa and West Asia. Despite the medical importance of T. schoenleinii infections, a high-quality reference genome for T. schoenleinii is still unavailable, neither its transcriptomic profile. OBJECTIVES: The aim of the current study was to improve understanding of the underlying pathogenic mechanism of T. schoenleinii, and to define the candidate pathogenic genes of T. schoenleinii. METHODS: Comprehensive genomic analysis of T. schoenleinii was carried out by Illumina and PacBio sequencing platforms. Transcriptome profiles of T. schoenleinii cultured in vitro in two media containing either keratin or soy protein were determined using RNA sequencing (RNA-seq) technology. RESULTS: Here, we present the first draft genome sequence of T. schoenleinii strain T2s, which consists of 11 scaffolds containing 7474 predicted genes. Transcriptome analysis showed that genes involved in keratin hydrolysis have higher expression in T. schoenleinii grown in keratin medium, including genes encoding proteases, cysteine dioxygenase and acetamidase. Other genes with higher expression include genes encoding the components of the pH-responsive signal transduction pathways and transcription factors, many of which may play a role in pathogenicity. CONCLUSION: In summary, this study provides new insights into the pathogenic mechanism of T. schoenleinii and highlights candidate genes for further development of novel targets in disease diagnosis and treatment of tinea favosa.

Tinea capitis in children: A single-institution retrospective review from 2011 to 2019.

Tinea capitis remains a common public health problem worldwide, especially in developing countries. OBJECTIVES: To investigate the changes of the predominant dermatophytes of tinea capitis in children in Hangzhou in recent 9 years. METHODS: The age, gender and pathogen spectrum of 650 children with tinea capitis at the Department of Dermatology, Affiliated Third People's Hospital of Hangzhou, Anhui Medical University from 2011 to 2019 were analysed, and the distribution of pathogens from 1998 to 2000 was compared. RESULTS: Among the 650 cases, 340 cases (48.2%) were males and 310 cases (51.8%) were females. The main population infected with tinea capitis was children aged 0-10 years (620 cases, 95.4%). From 2011 to 2019, the predominant dermatophyte was changed from Trichophyton violaceum (2011) to Trichophyton mentagrophytes complex (2012-2015) and later to Microsporum canis (2016-2019). In the past 9 years, M. canis (250 cases, 38.5%) was the most common dermatophyte and followed by T mentagrophytes complex (209 cases, 32.2%). The dermatophyte spectrum was statistically different between the years 2011 and 2019 (Chi square: χ2  = 69.75, P < .05), and the differences in anthropophilic and zoophilic pathogens between 1989-2000 and 2011-2019 were statistically significant (χ2  = 24.4, P < .05). CONCLUSIONS: Research showed that children diagnosed with tinea capitis were mainly 0-10 years old. With age, the percentage of anthropophilic dermatophytes gradually increased, while the percentage of zoophilic dermatophytes decreased. M. canis was the predominant dermatophyte of tinea capitis in children, followed by T. mentagrophytes complex. The dermatophytes have shifted from anthropophilic to zoophilic dermatophytes in the past two decades.

Clinical and epidemiological characteristics of tinea capitis in northern Taiwan during 2014-2019: An unusual bimodal distribution of patients and comparison of paediatric and adult cases.

Tinea capitis (TC) mainly occurs in children, and related studies in adults are rare. We aimed to investigate the current epidemiological, clinical and mycological characteristics of TC and to compare adult and paediatric patients in northern Taiwan. We conducted a retrospective study at Chang Gung Memorial Hospital, Linkou Branch, from 2014 to 2019. The dataset included age, sex, records of underlying diseases, animal contact history, frequent hair salon visits, clinical patterns, treatment and outcome via chart or phone call reviews. The average ages of 72 children and 104 adults recruited were 6.0 and 74.0 years, respectively. A female predominance was noted in both groups, and the ratio of females was significantly higher in adults (94.2% vs 59.7%, P < .0001). Microsporum canis (76.4%) and Trichophyton mentagrophytes (11.1%) in children, and M. canis (49.0%) and T. violaceum (31.7%) in adults were the most common pathogens. Adults were more likely to be infected with T. violaceum (OR = 10.14, 95% CI = 2.04-50.26) than children. In contrast, adults were less likely to be infected with M. canis than children (OR = 0.31, 95% CI = 0.11-0.90). Furthermore, adults visited hair salons more, had less animal contact and were more immunosuppressed than children. TC is not unusual in the adult population. Dermatologists are advised to realise risk factors such as immunosuppression and regular hair salon visit in adult TC.

Matrix-assisted laser desorption/ionisation-time of flight mass spectrometry: Protocol standardisation, comparison and database expansion for faster and reliable identification of dermatophytes.

BACKGROUND: Accurate and early identification of dermatophytes enables prompt antifungal therapy. However, phenotypic and molecular identification methods are time-consuming. MALDI-TOF MS-based identification is rapid, but an optimum protocol is not available. OBJECTIVES: To develop and validate an optimum protein extraction protocol for the efficient and accurate identification of dermatophytes by MALDI-TOF MS. MATERIALS/METHODS: Trichophyton mentagrophytes complex (n = 4), T. rubrum (n = 4) and Microsporum gypseum (n = 4) were used for the optimisation of protein extraction protocols. Thirteen different methods were evaluated. A total of 125 DNA sequence confirmed clinical isolates of dermatophytes were used to create and expand the existing database. The accuracy of the created database was checked by visual inspection of MALDI spectra, MSP dendrogram and composite correlation index matrix analysis. The protocol was validated further using 234 isolates. RESULT: Among 13 protein extraction methods, six correctly identified dermatophytes but with a low log score (≤1.0). The modified extraction protocol developed provided an elevated log score of 1.6. Significant log score difference was observed between the modified protocol and other existing protocols (T. mentagrophytes complex: 1.6 vs. 0.2-1.0, p < .001; T. rubrum: 1.6 vs. 0.4-1.0, p < .001; M. gypseum:1.6 vs. 0.2-1.0, p < .001). Expansion of the database enabled the identification of all 234 isolates (73.5% with log score ≥2.0 and 26.4% with log scores range: 1.75-1.99). The results were comparable to DNA sequence-based identification. CONCLUSION: MALDI-TOF MS with an updated database and efficient protein extraction protocol developed in this study can identify dermatophytes accurately and also reduce the time for identifying them.

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.

Dermatophytic melanonychia: A case series of an increasing disease.

BACKGROUND: Melanonychia refers to brown-black colour pigmentation due to melanin or not-melanin deposition in the nail plate. Onychoscopy allows to distinguish if the pigmentation is due by melanin or not. The main causes of non-melanic pigmentation are subungual haematoma and pigmented onychomycosis. Fungal melanonychia (FM) is rare and may present as diffuse or longitudinal pigmentation. Differential diagnosis includes melanic activation, such as ethnic-type nail pigmentation or frictional melanonychia, but also versus melanic proliferation, such as nevus or nail melanoma. Fungal melanonychia can be due to a colonisation by fungi with black variant or by melanin activation due to inflammation of fungal invasion. OBJECTIVES: The aim of paper is to increase clinical and dermoscopic knowledge of this increasingly frequent disease. METHODS: In this retrospective observational study, twenty patients with dermatophytic melanonychia were collected, with available clinical and dermoscopic pictures. The diagnosis of dermatophytic melanonychia was made based on clinical manifestation and mycological examination. KOH smear was performed in all cases. For each patient, clinical data included: age, gender, type of melanonychia and involved fingers. RESULTS: This study aimed to show increased incidence of dermatophytic melanonychia and its correct management. In addition, we reviewed our collected cases and described the clinical and dermoscopic features of dermatophytic melanonychia. CONCLUSIONS: The results of this study showed that physicians should keep in mind the diagnosis of this increasing disease, and that it cannot be performed relying only on clinical grounds. We would like to highlight the importance of tools as KOH examination, culture and dermoscopy.

In vitro antifungal susceptibility patterns of Trichophyton benhamiae complex isolates from diverse origin.

BACKGROUND: Species from the Trichophyton benhamiae complex are mostly zoophilic dermatophytes which cause inflammatory dermatophytosis in animals and humans worldwide. OBJECTIVES: This study was purposed to (a) to identify 169 reference and clinical dermatophyte strains from the T benhamiae complex species by molecular method and adhering to the newest taxonomy in the complex (b) to evaluate the in vitro antifungal susceptibility profile of these strains against eight common and new antifungal agents that may be used for the treatment of dermatophytosis. METHODS: All isolates, mainly originated from Europe but also from Iran, Japan and USA, were subjected to ITS-rDNA sequencing. The in vitro antifungal susceptibility profiles of eight common and new antifungal drugs against the isolates were determined by CLSI M38-A2 protocol and according to microdilution method. RESULTS: Based on the ITS-rDNA sequencing, T benhamiae was the dominant species (n = 102), followed by T europaeum (n = 29), T erinacei (n = 23), T japonicum (n = 10), Trichophyton sp (n = 4) and T eriotrephon (n = 1). MIC ranges across all isolates were as follows: luliconazole: 0.0002-0.002 µg/ml, terbinafine: 0.008-0.125 µg/ml, efinaconazole: 0.008-0.125 µg/ml, ciclopirox olamine: 0.03-0.5 µg/ml, itraconazole: 0.06-2 µg/ml, griseofulvin: 0.25-4 µg/ml, amorolfine hydrochloride: 0.125-4 µg/ml and tavaborole: 1-16 µg/ml. CONCLUSION: Luliconazole, efinaconazole and terbinafine were the most potent antifungals against T benhamiae complex isolates, regardless of the geographic locations where strains were isolated. These data might help dermatologists to develop effective therapies for successful treatment of infections due to T benhamiae complex species.

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.

Evaluation of DermaGenius® resistance real-time polymerase chain reaction for rapid detection of terbinafine-resistant Trichophyton species.

BACKGROUND: Treatment-resistant dermatophytosis caused by Trichophyton mentagrophytes/interdigitale complex has emerged as a global public health threat, particularly in endemic countries like India and has spread to many other countries. This veritable spread is alarming due to increase in resistance to terbinafine, which targets the ergosterol biosynthetic pathway by inhibiting the enzyme squalene epoxidase (SQLE). About two third of studies worldwide have reported amino acid substitutions Phe397Leu and Leu393Phe in the SQLE protein to be responsible for high terbinafine MICs. OBJECTIVES: We evaluated the efficacy of the newly developed DermaGenius® Resistance real-time PCR assay to rapidly identify Trichophyton isolates harbouring most common SQLE mutant (Phe397Leu and Leu393Phe) conferring high terbinafine resistance from wild-type susceptible isolates. METHODS: A total of 97 Trichophyton isolates confirmed by ITS sequencing as T. mentagrophytes/interdigitale (recently named T. indotineae n = 90), T. rubrum/T. soudanense (n = 3), T mentagrophytes (n = 2) and T tonsurans (n = 2) were analysed to evaluate DermaGenius® Resistance real-time PCR assay. All 40 T. indotineae isolates exhibiting amino acid substitutions Phe397Leu or Leu393Phe identified by SQLE gene sequencing were evaluated for detection of non-wild-type strains by real-time PCR. Antifungal susceptibility testing for terbinafine was done by CLSI microbroth dilution method. RESULTS: All terbinafine-resistant isolates harbouring amino acid substitutions Phe397Leu or Leu393Phe in SQLE gene were correctly recorded as SQLE mutants by the DermaGenius® Resistance real-time PCR assay. CONCLUSIONS: The DermaGenius® Resistance real-time PCR assay effectively identified Trichophyton species and distinguished wild-type from SQLE mutant genotype that harbour Phe397Leu and Leu393Phe amino acid substitutions.

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.