Towards a Standardized Procedure for the Production of Infective Spores to Study the Pathogenesis of Dermatophytosis.

Emilie Faway,Cindy Staerck,Yves Poumay,Sophie Vroomen,Christel Courtain,Bernard Mignon,Célya Danzelle

doi:10.3390/jof7121029

Emilie Faway, Cindy Staerck + Show 5 more

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https://doi.org/10.3390/jof7121029

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Abstract

Dermatophytoses are superficial infections of human and animal keratinized tissues caused by filamentous fungi named dermatophytes. Because of a high and increasing incidence, as well as the emergence of antifungal resistance, a better understanding of mechanisms involved in adhesion and invasion by dermatophytes is required for the further development of new therapeutic strategies. In the last years, several in vitro and in vivo models have emerged to study dermatophytosis pathogenesis. However, the procedures used for the growth of fungi are quite different, leading to a highly variable composition of inoculum for these models (microconidia, arthroconidia, hyphae), thus rendering difficult the global interpretation of observations. We hereby optimized growth conditions, including medium, temperature, atmosphere, and duration of culture, to improve the sporulation and viability and to favour the production of arthroconidia of several dermatophyte species, including Trichophyton rubrum and Trichophyton benhamiae. The resulting suspensions were then used as inoculum to infect reconstructed human epidermis in order to validate their ability to adhere to and to invade host tissues. By this way, this paper provides recommendations for dermatophytes culture and paves the way towards a standardized procedure for the production of infective spores usable in in vitro and in vivo experimental models.

Highlights

Dermatophytoses are superficial infections of the skin, hair, and nails due to filamentous and keratinolytic fungi named dermatophytes [1]
The growth of dermatophytes was monitored on different media (SAB, potato dextrose agar (PDA), yeast peptone dextrose (YPD), MALT, and yeast extract nitrogen (YEN)) by determination of colony diameter and radial growth
Faced with a still increasing incidence of dermatophytosis [2], together with the emergence of antifungal resistance [10,11,12,13,14], a better understanding of fungal mechanisms involved in the pathogenesis of dermatophytosis, as well as of cellular responses developed by the host, has become crucially awaited in order to rationally define new therapeutic strategies

Summary

Introduction

Dermatophytoses are superficial infections of the skin, hair, and nails due to filamentous and keratinolytic fungi named dermatophytes [1]. Classical antifungals, such as azole derivatives and terbinafine, are generally efficient to treat dermatophytosis [8], but their use is associated with potential toxicity when systemic administration is required [9] and must cope with the growing emergence of resistant strains [10,11,12,13,14] Because of this high and still increasing prevalence of dermatophytosis, as well as the difficulties encountered with currently available treatments, more research is needed to elucidate mechanisms responsible for fungal adherence and invasion of the host tissue. Several in vitro and in vivo models of infection by dermatophytes have been developed (for reviews, see [15,16] respectively)

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