Avaliação antifúngica de nanoestruturas de tungstato de prata contra leveduras e fungos dermatófitos
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Data
2021-10-08
Autores
Bianco, Letícia Monteiro
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Universidade Estadual Paulista (Unesp)
Resumo
As infecções fúngicas representam um significante problema de saúde pública no cenário mundial e estão aumentando em incidência, principalmente em hospedeiros imunocomprometidos. A micose superficial é caracterizada pela infecção no estrato córneo, com baixa resposta inflamatória, e corresponde a principal causa de doença de pele, que afeta milhões de pessoas causadas por fungos dermatófitos, não dermatófitos ou leveduras. A alta tolerância e resistência dos fungos aos antifúngicos convencionais têm sido observado, esses fatores implicam na procura de compostos que sejam eficazes, que reduzam o tempo de tratamento e não apresentem riscos ao paciente. O tungstato de prata é um composto de tungstênio e prata, que ao ser irradiado com elétrons crescem partículas de prata com ação plasmônica, tornando-o mais bactericida e fungicida. O objetivo deste trabalho foi realizar a síntese das nanoestruturas de tungstato, pelo método de coprecipitação simples. A atividade antifúngica, in vitro, foi avaliada por microdiluição, obtendo-se a Concentração Inibitória Mínima (MIC) do tungstato de prata contra linhagens clínicas e cepas de referências (ATCC) de Candida spp., Trichophyton rubrum, Trichophyton mentagrophytes e Microsporum canis, apresentando atividade antifúngica efetiva com valores de MIC entre 0,03-62,5 µg/mL. Cepas de C. krusei mostrou-se mais sensível e cepas de C. albicans mais resistentes ao composto sintetizado. O ensaio de toxicidade foi realizado em modelo in vivo usando larvas de Galleria mellonella. O teste foi executado por inoculação com a mesma concentração de α-Ag2WO4 usada nos testes de microdiluição anteriores, e não apresentou toxicidade. O ensaio de time kill foi realizado com cepas clínicas e referências das espécies de Candida e dermatófitos. Esses resultados mostram uma potencial aplicação no controle de infecções fúngicas inovando os protocolos terapêuticos.
Fungal infections represent a significant public health problem worldwide and are on the increase, especially in immunocompromised hosts. Superficial mycosis is characterized by infection in the stratum corneum, with a low inflammatory response, and is the main cause of skin disease, which affects millions of people caused by dermatophyte, non-dermatophyte or yeast fungi. The high tolerance and resistance of fungi to conventional antifungals has been observed, these factors imply the search for compounds that are effective, that reduce the treatment time and do not present risks to the patient. Silver tungstate is a compound of tungsten and silver, which when irradiated with electrons grow silver particles with plasmatic action, making it more bactericidal and fungicidal. The objective of this work was to carry out the synthesis of tungstate nanostructures, by the simple co-precipitation method. The in vitro antifungal activity was evaluated by microdilution, obtaining the Minimum Inhibitory Concentration (MIC) of silver tungstate against clinical strains and reference strains (ATCC) of Candida spp., Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis, showing effective antifungal activity with MIC values between 0,03-62,5 µg/mL. C. krusei strains were more sensitive and C. albicans strains more resistant to the synthesized compound. The toxicity test was performed in an in vivo model using Galleria mellonella larvae. The test was performed by inoculation with the same concentration of α-Ag2WO4 used in the previous microdilution tests, and showed no toxicity. The time kill assay was carried out with clinical strains and references of Candida species and dermatophytes. These results show a potential application in the control of fungal infections by innovating therapeutic protocols.
Fungal infections represent a significant public health problem worldwide and are on the increase, especially in immunocompromised hosts. Superficial mycosis is characterized by infection in the stratum corneum, with a low inflammatory response, and is the main cause of skin disease, which affects millions of people caused by dermatophyte, non-dermatophyte or yeast fungi. The high tolerance and resistance of fungi to conventional antifungals has been observed, these factors imply the search for compounds that are effective, that reduce the treatment time and do not present risks to the patient. Silver tungstate is a compound of tungsten and silver, which when irradiated with electrons grow silver particles with plasmatic action, making it more bactericidal and fungicidal. The objective of this work was to carry out the synthesis of tungstate nanostructures, by the simple co-precipitation method. The in vitro antifungal activity was evaluated by microdilution, obtaining the Minimum Inhibitory Concentration (MIC) of silver tungstate against clinical strains and reference strains (ATCC) of Candida spp., Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis, showing effective antifungal activity with MIC values between 0,03-62,5 µg/mL. C. krusei strains were more sensitive and C. albicans strains more resistant to the synthesized compound. The toxicity test was performed in an in vivo model using Galleria mellonella larvae. The test was performed by inoculation with the same concentration of α-Ag2WO4 used in the previous microdilution tests, and showed no toxicity. The time kill assay was carried out with clinical strains and references of Candida species and dermatophytes. These results show a potential application in the control of fungal infections by innovating therapeutic protocols.
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Palavras-chave
Infecções fúngicas, Nanoestruturas de tungstato de prata, Dermatófitos, Leveduras, Fungal infections, Silver tungstate nanostructures, Dermatophytes, Yeasts