Evaluación del perfil de sensibilidad in vitro de aislamientos clínicos deTrichophyton mentagrophytes y Trichophyton rubrum en Santiago, Chile / Evaluation of the in vitro susceptibility pattern of clinical isolates of Trichophyton mentagrophytes and Trichophyton rubrum in Santiago, Chile

Antecedentes: Los dermatofitos son un grupo de hongos queratinolíticos que producen infecciones denominadas dermatofitosis o tiñas. En Chile, los dermatofitos aislados con mayor frecuencia son Trichophyton rubrumy Trichophyton mentagrophytes en la población adulta, y Microsporum canis en niños prepúberes. Para el tratamiento de estas micosis se emplean antifúngicos tópicos y orales como la griseofulvina, antifúngicos azólicos como el clotrimazol, el itraconazol o el fluconazol, alilaminas como la terbinafina, y nuevas moléculas antifúngicas. Objetivos: Evaluar la sensibilidad in vitro de los dermatofitos frente a cinco antifúngicos y establecer posibles cambios respecto a estudios anteriores. Métodos: Se estudiaron 62 dermatofitos obtenidos de muestras clínicas (marzo-junio de 2010). Se utilizó el método de microdilución en caldo (M38-A2). Resultados: El rango de CMI para el fluconazol fue de 0,25-1 μg/ml; 0,03-0,06 μg/ml para el clotrimazol, la terbinafina y el itraconazol, y 0,015-0,03 μg/ml para la griseofulvina frente a T. rubrum y T. mentagrophytes. Excepto para le fluconazol, no se encontraron diferencias estadísticas significativas en los rangos de sensibilidad antifúngica. Conclusiones: Los valores de CMI para el fluconazol fueron los más altos (0,25-1 μg/ml) de todas las sustancias ensayadas, habiendo diferencias estadísticamente significativas entre este y el resto de antifúngicos. No hubo cepas resistentes a los antifúngicos analizados, y tampoco se encontraron cambios en el perfil de sensibilidad antifúngica in vitro en relación con estudios anteriores realizados en Chile (AU)

Background: Dermatophytes are a group of keratinophilic fungi able to produce dermatophytosis or tinea infections. In Chile, Trichophyton rubrum and Trichophyton mentagrophytes are the ones most commonly isolated in adults, while Microsporum canis is found among children. Treatment of these infections is usually with topical or oral antifungals, such as griseofulvin or azole derivatives (clotrimazole, itraconazole, fluconazole), allylamines (terbinafine) or new drugs that are available. Aims: Evaluation of the in vitro susceptibility of dermatophytes to five antifungal agents and the comparison of the susceptibility pattern with that of previous years. Methods: Sixty-two clinical isolates of dermatophyte fungi were studied (March-June 2010). The CLSI M38-A2 micromethod was used. Results: Fluconazole MIC values for T. rubrum and T. mentagrophytes varied between 0.25 and 1 μg/ml; MIC range to clotrimazole, terbinafine and itraconazole was 0.03-0.06 μg/ml, and MIC values for griseofulvin were 0.015-0.03 μg/ml. No statistically significant differences were found between susceptibility patterns, except for fluconazole. Conclusions: Fluconazole was less active in comparison with other drugs tested (0.25-1 μg/ml). None of the isolates were resistant to any of the drugs, and no changes in the susceptibility pattern were observed when comparing the results with data previously reported concerning dermatophytes in Chile (AU)

[Evaluation of the in vitro susceptibility pattern of clinical isolates of Trichophyton mentagrophytes and Trichophyton rubrum in Santiago, Chile]. / Evaluación del perfil de sensibilidad in vitro de aislamientos clínicos de Trichophyton mentagrophytes y Trichophyton rubrum en Santiago, Chile.

BACKGROUND: Dermatophytes are a group of keratinophilic fungi able to produce dermatophytosis or tinea infections. In Chile, Trichophyton rubrum and Trichophyton mentagrophytes are the ones most commonly isolated in adults, while Microsporum canis is found among children. Treatment of these infections is usually with topical or oral antifungals, such as griseofulvin or azole derivatives (clotrimazole, itraconazole, fluconazole), allylamines (terbinafine) or new drugs that are available. AIMS: Evaluation of the in vitro susceptibility of dermatophytes to five antifungal agents and the comparison of the susceptibility pattern with that of previous years. METHODS: Sixty-two clinical isolates of dermatophyte fungi were studied (March-June 2010). The CLSI M38-A2 micromethod was used. RESULTS: Fluconazole MIC values for T. rubrum and T. mentagrophytes varied between 0.25 and 1 µg/ml; MIC range to clotrimazole, terbinafine and itraconazole was 0.03-0.06 µg/ml, and MIC values for griseofulvin were 0.015-0.03 µg/ml. No statistically significant differences were found between susceptibility patterns, except for fluconazole. CONCLUSIONS: Fluconazole was less active in comparison with other drugs tested (0.25-1 µg/ml). None of the isolates were resistant to any of the drugs, and no changes in the susceptibility pattern were observed when comparing the results with data previously reported concerning dermatophytes in Chile.

Una nueva generación de antifúngicos para el tratamiento de las micosis superficiales / A new generation of antifungals for the treatment of dermatomycosis

Las infecciones fúngicas superficiales responden bien a los tratamientos habituales en la mayoría de los casos pero, en determinadas situaciones, constituyen un problema. En su mayoría se trata de infecciones producidas por levaduras del género Candida y Malassezia y por hongos dermatofitos. Estas infecciones han visto incrementada su prevalencia junto con la selección de determinadas especies, la reducción de la sensibilidad a los antifúngicos y la aparición de fenómenos de resistencia in vitro e in vivo. La investigación para encontrar el antifúngico ideal aún continúa y en este sentido actualmente se están ensayando distintas estrategias de investigación sobre drogas para el tratamiento sistémico y tópico de las dermatomicosis.

Superficial fungal infections frequently caused by Candida spp. and Malassezia spp yeasts and dermatophytes fungi, have good response to common treatments in the majority of cases, but in some cases failure are described. Prevalence of these infections has been increased with the selection of certain species, reduced sensitivity to antifungal agents and the emergence of in vitro and in vivo resistance phenomena. The research to find the ideal antifungal still continues and in this sense are being currently tested different strategies for research on systemic and topical drugs for dermatomycosis treatment.