Actividad antifúngica de melanina en cepas clínicas de Candida spp

Background: Melanocytes are cells located in epidermis and mucous membranes that synthesize melanin and cytokines. It is known that melanin has antimicrobial activity and that melanocytes are melanized in presence of microbial molecules. Objective: To study the antifungal activity of melanin on Candida spp. Methodology: The minimum inhibitory concentration (MIC) to melanin was determined in 4 Candida ATCC strains (C. albicans SC5314, C. parapsilosis 22019, C. glabrata 2001, C. krusei 6258) and 56 clinical isolates of Candida spp. (33 C. albicans, 12 C. glabrata, 3 C. famata, 3 C. krusei, 3 C. parapsilosis, 2 C. tropicalis) using a broth microdilution method. In addition, the antifungal activity of melanocytes and mice melanoma cells was tested against C. albicans. Results: Melanin inhibited the tested isolates, including the susceptible dose-dependent and fluconazole-resistant strains; MIC range and MIC50 were 0.09-50 μg/mL and 6.25 μg/mL, respectively. Pigmented cells lysates inhibited C. albicans. Conclusions: Melanin is able to inhibit clinical isolates of Candida spp. Melanization could be an important protective mechanism of melanocytes. Introduccion: Los melanocitos son celulas presentes en piel y en mucosas que sintetizan melanina, ademas de citoquinas. Es sabido que melanina presenta actividad antimicrobiana y que los melanocitos se melanizan al ser expuestos a moleculas microbianas. Objetivo: Estudiar la actividad antifungica de melanina en cepas clinicas de Candida spp. Metodologia: Se midio la concentracion inhibitoria minima (CIM) a melanina, de 4 cepas de Candida ATCC (C. albicans SC5314, C. parapsilosis 22019, C. glabrata 2001 y C. krusei 6258) y 56 aislados clinicos de Candida spp. (33 C. albicans, 12 C. glabrata, 3 C. famata, 3 C. krusei, 3 C. parapsilosis, 2 C. tropicalis) mediante un metodo de microdilucion en caldo. Ademas se estudio el efecto antifungico de lisados de melanocitos y celulas de melanoma de raton en C. albicans. Resultados: Melanina inhibio las cepas analizadas, incluso cepas susceptibles dosis-dependiente y resistentes a fluconazol, siendo los rangos de CIM y CIM50 de 0,09-50 μg/mL y 6,25 μg/ mL, respectivamente. Los lisados de celulas pigmentadas inhibieron C. albicans. Conclusiones: Melanina es capaz de inhibir cepas clinicas de Candida spp. La melanizacion podria ser un importante mecanismo protector de los melanocitos.