Tinea unguium onychomycosis caused by dermatophytes: a ten-year (2005-2014) retrospective study in a tertiary hospital in Singapore.

INTRODUCTION: Tinea unguium is a common nail infection. We conducted a retrospective ten-year study of the patient demographics and species distribution of dermatophytes causing tinea unguium in a tertiary hospital from Singapore. METHODS: Results of fungal nail cultures were retrieved from our hospital's microbiology department. Samples from nail scrapings and clippings were inoculated onto agar plates (Sabouraud dextrose agar with chloramphenicol and Mycosel agar). Nail specimens that grew dermatophytes were included in the study. RESULTS: Overall, 229 (male: n = 164, 71.6%; female: n = 65, 28.4%) nail specimens grew dermatophytes. Mean patient age was 58 (range 18-93) years. A majority of specimens came from patients aged over 50 years (n = 162, 70.7%) and 60-79 years (n = 100, 43.7%). Ethnically, 160 (69.9%) patients were Chinese, 36 (15.7%) Indian, 18 (7.9%) Malay and 15 (6.6%) of other ethnicities. Among dermatophytes isolated were Trichophyton rubrum (n = 93, 40.6%), Trichophyton mentagrophytes (n = 60, 26.2%), unidentified Trichophyton spp. (n = 57, 24.9%), Trichophyton tonsurans (n = 10, 4.4%), Epidermophyton floccosum (n = 5, 2.2%), Trichophyton verrucosum (n = 2, 0.9%), Trichophyton soudanense (n = 1, 0.4%) and Trichophyton violaceum (n = 1, 0.4%). CONCLUSION: A majority of isolates were from elderly patients. Compared to Singapore's general population, patients of Indian and other ethnicities were over-represented for tinea unguium when compared to Chinese and Malay patients. Trichophyton rubrum was the most common dermatophyte isolated, while Trichophyton verrucosum, Trichophyton violaceum and Trichophyton soudanense were rare causes of tinea unguium.

Pathogenesis of Dermatophytosis: Sensing the Host Tissue.

The genera Trichophyton, Microsporum, and Epidermophyton include filamentous fungi that cause dermatophytosis, a superficial infection of the skin, stratum corneum, nail beds, and hair follicles. The ability of dermatophytes to adhere to these substrates and adapt to the host environment is essential for the establishment of infection. Several fungal enzymes and proteins participate in this adaptive response to the environment and to keratin degradation. Transcription factors such as PacC and Hfs1, as well as heat shock proteins, are involved in sensing and adapting to the acidic pH of the skin in the early stages of fungal-host interaction. During dermatophyte growth, with keratin as the sole carbon source, the extracellular pH shifts from acidic to alkaline. This creates an environment in which most of the known keratinolytic proteases exhibit optimal activity. These events culminate in the establishment and maintenance of the infection, which can be chronic or acute depending on the dermatophyte species. This review focuses on these and other molecular aspects of the dermatophyte-host interaction.

Haemolytic and co-haemolytic (CAMP-like) activity in dermatophytes.

Dermatophytes are some of the most common fungal pathogens in both humans and animals. These fungi release enzymes (e.g., keratinases) that play roles in their pathogenesis. Little is known about their haemolytic and co-haemolytic (CAMP-like) activities; however, in bacteria, these components play significant roles in pathogenesis. This study characterised these two factors in 45 dermatophyte strains (representing the genera Arthroderma, Epidermophyton, Microsporum and Trichophyton) using Columbia agar (CA) supplemented with 5% bovine, ovine and equine erythrocytes. Haemolysis was best observed on CA supplemented with ovine erythrocytes followed by equine and bovine erythrocytes, while CAMP-like reactions occurred using bovine and ovine but not equine erythrocytes. Haemolytic and CAMP-like activities were best observed using ovine and bovine erythrocytes in CA in 44 and 38 strains at 7 and 3 days respectively. Most dermatophytes recovered from both symptomatic and asymptomatic lesions had haemolytic and CAMP-like activities. We suggest that the haemolytic and CAMP-like activities are not correlated with ecological characteristics, isolation sites or clinical manifestations of dermatophytic fungi. We also believe that this study has the potential to contribute to the existing literature on dermatophytes and dermatophyte pathogenesis.

Aproximación al manejo de la patología micótica en el pie / Approach to the management of fungal infection in the foot

El término micosis engloba a las patologías causadas por hongos en el ser humano. Por su prevalencia, en la actualidad, se puede afirmar, que se ha llegado a comparar, a la caries dental y a los resfriados, debido sin duda alguna al alto porcentaje de pacientes que la padecen. Además, de que estudios epidemiológicos recientes, han demostrado que a parte de alterar per se la calidad de vida, (relaciones personales, nivel psicológico, deambulación...) También, pueden dar lugar a complicaciones poco deseables, provocando cuadros infecciosos y bacterianos, que suponen un alto gasto sociosanitario al ocasionar perturbación ocupacional, deterioro psicológico y físico, y una potencial estigmatización social. La carencia de consenso en relación a la etiología multifactorial que presenta esta afección y la prevalencia de esta enfermedad a nivel del pie, sobre todo en los jóvenes y en los deportistas, nos lleva a mejorar los conocimientos existentes en lo que se refiere a su clasificación, diagnóstico y tratamiento en la búsqueda de actualizar los conceptos relacionados con esta patología del pie (AU)

The term encompasses fungal fungal diseases in humans. Because of its prevalence, today, we can say, that has been compared to dental caries and colds due undoubtedly to the high percentage of patients with the disease. Moreover, that recent epidemiological studies have shown that part per se alter the quality of life (personal, psychological level, walking...) also may result in undesirable complications, causing infectious diseases, and bacterial, involving high expenditure by causing disruption socio occupational psychological and physical deterioration, and potential social stigmatization. The lack of consensus regarding the multifactorial etiology has this condition and the prevalence of this disease at foot level, especially in the young and in athletes, leads us to improve existing knowledge in regard to classification diagnosis and treatment in the quest to update the concepts related to this foot disorders (AU)

Aspectos clínicos, diagnósticos y terapéuticos de las dermatofitosis / Clinical, diagnostic and therapeutic aspects of dermatophytosis

Los dermatofitos son un grupo de hongos, estrechamente relacionados entre sí, que poseen queratinasa y, por ello, son capaces de causar infecciones en tejidos queratinizados (piel, pelo y uñas) del hombre y animales, denominadas dermatofitosis. Según la procedencia de la queratina que utilizan, los dermatofitos se clasifican en geofílicos (suelo), zoofílicos (animales) y antropofílicos (hombre), siendo el suelo, algunos animales y el hombre sus respectivos reservorios naturales. Pertenecen a este grupo los géneros Epidermophyton, Microsporum y Trichophyton, constituyendo un total aproximado de 40 especies. Muchos dermatofitos pueden presentarse en la naturaleza en estado anamorfo (con reproducción asexual) o imperfecto y teleomorfo (con reproducción sexual) o perfecto. Los estados anamorfos (géneros Epidermophyton, Microsporum y Trichophyton) pertenecen a la clase Hyphomycetes del filum Deuteromycota (hongos imperfectos) y los estados teleomorfos (mayoría de especies zoofílicas y geofílicas de Microsporum y Trichophyton) están clasificados en el género teleomórfico Arthroderma, orden Onygenales y filum Ascomycota. Habitualmente los encontraremos como anamorfos. La distribución de los dermatofitos es universal, siendo responsables de la mayoría de las infecciones fúngicas superficiales, tanto en personas sanas como en pacientes inmunocomprometidos. El diagnóstico y tratamiento de las dermatofitosis son sobradamente conocidos por la gran mayoría de los microbiólogos; no obstante, se citarán técnicas novedosas para su diagnóstico, así como tratamientos actualizados. El (..)) (AU)

Dermatophytes are a group of closely related fungi that have keratinase and can therefore cause infections in keratinised human and animal tissues (skin, hair and nails), leading to a disease known as dermatophytosis. This group is composed by the genera Epidermophyton, Trichophyton and Microsporum, forming an approximated total of 40 species. Depending on the source of the keratin used, dermatophytes can be divided in geophilic (soil), zoophilic (animals) and anthropophilic (human), with soil, some animalsand humans being their primary habitats. Many dermatophytes can be present in both anamorphic (asexualstate) or imperfect and teleomorphic state (with sexual reproduction) or perfect fungi. Anamorphic states(genera Epidermophyton, Microsporum and Trichophyton ) belong to the Hyphomycetes and phylum Deuteromycota class and teleomorphic states (the majority of geophilic and zoophilic species of Microsporum and Trichophyton) are classified in the teleomorphic genus Arthroderma, order Onygenales, phylum Ascomycota, and are usually found in their anamorphic state. Dermatophytes have a worldwide distribution, being responsible for most of the skin mycoses in both healthy and immunocompromised patients. The diagnosis and treatment of dermatophytosis are well known by most microbiologists and scientists in general. However, we describe recent techniques for their diagnosis and up-to-date treatments. The main purpose of this review is to provide a detailed description of the three genera of dermatophytes, with special mention of Epidermophyton floccosum, a object of the SEIMC’s mycology quality control (M-2/09) (AU)

Dermatofitosis por hongos antropofílicos en Cádiz (1997–2008) / Dermatophytoses due to anthropophilic fungi in Cadiz, Spain, between 1997 and 2008

Introducción y objetivos: Las infecciones cutáneas producidas por hongos constituyen un importante problema de salud pública. La distribución de las dermatofitosis varía en diferentes países y áreas geográficas. El objetivo de este estudio ha sido determinar la epidemiología, etiología y evolución de las dermatofitosis por hongos antropofílicos en Cádiz durante los últimos 12 años. Material y métodos: El estudio se realizó de 1997 – 2008 sobre 2.235 muestras de lesiones de piel, pelo y uñas de 2.220 pacientes con sospecha clínica de micosis. Las muestras fueron analizadas mediante examen microscópico con hidróxido potásico y cultivo en medios micológicos. Los dermatofitos se identificaron de acuerdo con las características macroscópicas y microscópicas. Resultados: El cultivo fue positivo en 283 muestras (12,7%). Los dermatofitos antropofílicos (53,3%) predominaron sobre los zoofílicos (41,3%) y geofílicos (5,3%). Trichophyton rubrum (38,2%) fue el patógeno más frecuente, seguido de Microsporum canis (22,3%) y Trichophyton mentagrophytes (15,5%). Se identificaron otras cinco especies de hongos antropofílicos: T. tonsurans (5,6%), T. violaceum (4,9%), Epidermophyton floccosum (2,8%), T. soudanense (1,0%) y T. schoenleinii (0,7%). Las infecciones por hongos antropofílicos fueron onicomicosis (29,1%), tiña corporal (25,8%), tiña del pie (19,2%), tiña crural (11,9%), tiña del cuero cabelludo (5,3%) y tiña facial (3,3%). Conclusiones: El principal responsable de dermatofitosis en Cádiz es Trichophyton rubrum. Su incidencia es ascendente desde el año 2000. Otros hongos antropofílicos como T. tonsurans y T. violaceum son cada vez más prevalentes, aunque no están directamente relacionados con la inmigración. Epidermophyton floccosum, T. soudanense y T. schoenleinii se aíslan ocasionalmente (AU)

Background and objectives: Cutaneous fungal infections are a major public health problem. The distribution of the dermatophytoses varies between countries and geographical areas. The aim of this study was to determine the incidence, epidemiology, etiology, and clinical course of the dermatophytoses caused by anthropophilic fungi in Cadiz, Spain, over the past 12 years. Material and methods: The study, conducted between 1997 and 2008, included 2,235 samples from lesions of the skin, hair, and nails of 2,220 patients with a clinical suspicion of mycosis. Samples were examined by microscopy using potassium hydroxide and were cultured on mycological media. The dermatophytes were identified by their macroscopic and microscopic characteristics. Results: Cultures were positive in 283 cases (12.7%). Anthropophilic dermatophytes (53.3%) were more common than zoophilic (41.3%) and geophilic (5.3%) dermatophytes. Trichophyton rubrum (38.2%) was the predominant pathogen isolated, followed by Microsporum canis (22.3%) and Trichophyton mentagrophytes (15.5%). Five other species of anthropophilic fungi were identified: Trichophyton tonsurans (5.6%), Trichophyton violaceum (4.9%), Epidermophyton floccosum (2.8%), Trichophyton soudanense (1.0%), and Trichophyton schoenleinii (0.7%). Infections caused by the anthropophilic fungi included tinea unguium (29.1%), tinea corporis (25.8%), tinea pedis (19.2%), tinea cruris (11.9%), tinea capitis (5.3%), and tinea faciei (3.3%). Conclusions: The principal fungus responsible for dermatomycosis in Cadiz was T. rubrum, and its incidence has been rising since 2000. The prevalence of other anthropophilic fungi, such as T. tonsurans and T. violaceum, has increased, though this is not directly related to immigration. E. floccosum, T. soudanense, and T. schoenleinii are isolated occasionally (AU)

Tiña corporis y tiña capitis / Tinea corporis and tinea capitis

La tiña es una infección de la piel, piel cabelluda, uñas o pelo causada por hongos dermatofíticos que invaden el estrato corneo y usan la queratina como nutriente. Existen tres géneros de dermatofitos: Trichophyton, Epidermophyton y Microspurum.

[Exoenzymes of dermatophytes isolated from acute and chronic tinea]. / Exoenzimas de dermatofitos aislados de tiñas agudas y crónicas.

The presence of five enzymes (deoxyribonuclease, elastase, lipase, caseinase and hemolysin) in 76 strains of dermatophytes 47 of Trichophyton rubrum, 10 of T. mentagrophytes, five of T. tonsurans, 10 of Microsporum canis and four of Epidermophyton floccosum) isolated from 30 cases of acute dermatophytosis and from 46 chronic ones was determined by a qualitative plate assay; in the same way, the presence of these five enzymes with the acute and chronic dermatophytosis was correlated. It was observed that three of the enzymes were produced by the strains with a meaningful frequency; deoxyribonuclease was produced by 84.2% of the strains; elastase by 82.9%; and lipase by 65.8%. In T. rubrum the DNase was produced in 100% of strains. DNase and elastase were related to fungi which caused acute or chronic dermatophytosis in 93.3/78.2% and 96.6/74% respectively. On the other hand, lipase was present in 76% of strains, the ones that caused the chronic infections.

Further observations on the keratinolytic activity of strains of the genus Epidermophyton.

The ability of 17 strains of Epidermophyton to perforate hair in vitro using the Ajello & Georg's test procedure and a modification of Lu's method has been studied. Following the Ajello & Georg's test procedure only E. stockdaleae perforated hair. Sporadically some strains of E. floccosum perforated horse hair. We noted as well unusual perforations originated from inside to outside of the hair. By the other technique, all strains, excepting E. floccosum var. nigricans in child hair, perforated hair. E. floccosum showed these perforations later than E. stockdaleae.

Experimental dermatophytoses produced by E. floccosum in guinea pigs.

Experimental dermatophytoses were tested in guinea pigs by 17 strains of genus Epidermophyton. Only three strains of E. floccosum produced lesions. These lesions were detected 5-7 d after inoculation, and no crust formation or alopecia was observed. These lesions were also studied using microbiological and histopathological techniques. No infection occurred after cutaneous application of E. floccosum var. nigricans and E. stockdaleae.