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Objective:To investigate the distribution of pathogenic fungi in patients with tinea capitis diagnosed in Xijing Hospital, Air Force Medical University in the past 10 years.Methods:A total of 871 outpatients or inpatients with tinea capitis were collected from the Department of Dermatology, Xijing Hospital from January 2011 to December 2020, and their clinical data and pathogen distribution were retrospectively analyzed. Pearson chi-square test was used to analyze differences in the pathogen distribution between children and adult patients with tinea capitis.Results:Of 871 patients with tinea capitis, 588 (67.5%) were males and 283 (33.5%) were females; 21 (2.40%) were aged less than 1 year, 266 (30.50%) aged 1 - 3 years, 352 (40.40%) aged 4 - 6 years, 187 (21.50%) aged 7 - 12 years, 4 (0.50%) aged 12 - 18 years, and 41 (4.70%) were aged 18 - 74 years. A total of 705 pathogenic strains were isolated from these patients, including 599 strains of Microsporum canis (85.0%) , 52 strains of Trichophyton mentagrophytes complex (7.4%) , 27 strains of Trichophyton tonsurans (3.8%) , and 18 strains of Trichophyton violaceum (2.6%) . Among the pathogenic fungi of tinea capitis, the proportion of Trichophyton violaceum was significantly higher in adults (8.8%) than in children (2.2%, P = 0.048) . Conclusions:In the past 10 years, the patients with tinea capitis in the Department of Dermatology, Xijing Hospital were mainly children aged 1 - 6 yearswhile adults, and adult patients with tinea capitis were uncommon. The main pathogen of tinea capitis was Microsporum canis, followed by Trichophyton mentagrophytes complex.
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Resumen Los miembros del complejo Trichophyton mentagrophytes representan el segundo grupo en frecuencia de aislamiento de dermatofitos, luego de Trichophyton rubrum. El citado complejo comprende 3grupos principales: 1) Trichophyton benhamiae y especies relacionadas; 2) Trichophyton simii y 2especies relacionadas, Trichophyton quinckeanum y Trichophyton schoenleinii, y 3) T. mentagrophytes, Trichophyton interdigitale y especies relacionadas. Todos estos organismos son difíciles de identificar a través de la morfofisiología. Se presenta en este informe un estudio descriptivo de 17 cepas clínicas aisladas e identificadas en el Laboratorio de Micología de la Universidad de Valparaíso como pertenecientes al complejo T. mentagrophytes, junto con la caracterización de 3cepas de referencia (T. mentagrophytes CBS 318.56, T. interdigitale CBS 428.63, Trichophyton erinacei CBS 511.73), con el objetivo de clasificarlas a nivel de especie. Se realizaron pruebas morfofisiológicas y moleculares por análisis de curvas de melting de alta resolución (high resolution melting analysis) y secuenciación de regiones ITS. Fenotípicamente, se identificaron 3especies incluidas en el complejo. Los análisis moleculares reclasificaron todas las cepas como pertenecientes a T. interdigitale. En conclusión, no se lograron establecer patrones morfofisiológicos confiables para poder diferenciar entre las especies del complejo.
Abstract Trichophyton mentagrophytes complex is the most frequent agent found in dermatophyte isolates after Trichophyton rubrum. It is divided into 3main groups: (1) Trichophyton benhamiae and related species; (2) Trichophyton simii and 2related species, Trichophyton quinckeanum and Trichophyton schoenleinii; and (3) T. mentagrophytes, T. interdigitale, and related species. They are all difficult to identify by morphophysiology. With the aim of classifying them at the species level, a descriptive study was performed on 17 isolated clinical strains identified in the Mycology Laboratory of the Universidad de Valparaíso as belonging to the T. mentagrophytes complex. They were compared with 3 reference strains (T. mentagrophytes CBS 318.56, T. interdigitale CBS 428.63, Trichophyton erinacei CBS 511.73). Morphophysiological and molecular tests were performed by high resolution melting analysis curves and ITS regions sequencing. Phenotypically, 3 species of the complex were identified. Molecular analyses reclassified all the species as belonging to T. interdigitale. In conclusion, no reliable morphophysiological patterns were established to differentiate between the species of the complex. Molecularly, all the strains studied were classified as T. interdigitale.
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BACKGROUND: Trichophyton mentagrophytes complex is a heterogeneous group. A new classification, based on molecular biology, has replaced the one based on morphology, physiology, and mating behavior. OBJECTIVE: T. mentagrophytes isolates from Korean patients were classified using the new method and compared with the classic classification. METHODS: During 2010-2011, fungal isolates were collected at the Catholic skin clinic from 562 patients infected with T. mentagrophytes; clinical characteristics were reviewed. Patients were divided into four groups based on the morphological characteristics of the isolates. Thirty-four strains of T. mentagrophytes were randomly selected from the four groups for mycological and molecular biology analyses, including analyses of morphological characteristics, ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequence, and rDNA nontranscribed spacer (NTS) typing. RESULTS: Among the 562 isolates, persicolor (41.6%) was the most common strain type, followed by the powdery (38.4%), downy (11.2%), and granular (8.7%) types. The granular type differed from the other three with respect to the isolation site, patient's age, seasonal variation, and microscopic characteristics. Among the selected 34 strains, the microscopic characteristics varied for each strain. The powdery, persicolor, and downy types had ITS sequences identical to those of the anthropophilic T. interdigitale/A. vanbreuseghemii. The ITS sequence of granular type was similar to that of zoophilic T. interdigitale/A. vanbreuseghemii. The granular type had different NTS types than the other types did. CONCLUSION: The T. mentagrophytes strains isolated were classified as T. interdigitale/A. vanbreuseghemii; the majority (91.7%) was anthropophilic and 8.3% were zoophilic and granular type.
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Humanos , Classificação , DNA Ribossômico , Métodos , Biologia Molecular , Fisiologia , Estações do Ano , Pele , TrichophytonRESUMO
Abstract Tinea faciei is a relatively uncommon dermatophyte infection entailing atypical clinical symptoms, usually misdiagnosed and treated with corticosteroids. The authors describe a case of tinea faciei on the right eyebrow caused by Trichophyton interdigitale. The patient was an 18-year-old girl, who had an inflammatory plaque with a scaly, pustular surface on the right eyebrow and upper eyelid, which had persisted for over 1 month. She was once misdiagnosed as having eczema and was treated using corticosteroid cream. A diagnosis of tinea faciei was made based on direct microscopy and culture. The sequencing of the nuclear ribosomal ITS region and β-tubulin gene of the isolate established its T. interdigitale lineage. The patient was cured by treatment with systemic terbinafine in combination with topical application of 1% naftifine-0.25% ketaconazole cream for 2 weeks.