Análise Micológica de Solos Costeiros do Litoral do Piauí: Foco em Fungos Negros

Abstract

Black yeasts have stood out for causing damage to life and human well-being, as they can cause superficial and subcutaneous changes, in addition to fatal systemic infections. There is a growing interest in the characterization of yeast populations that live in coastal environments, such as beaches, focusing on pathogenic species, such as which represent a threat to the health of those frequent in these places. The survey of the quality conditions of the beaches of the Piauí Coast is not a common practice, there is no data on the microbiological quality of the soil of the beaches and the Delta of the River Parnaíba, there are only studies that address the water quality of these places. So, the objective of this work is to characterize and quantify the fungi present coastal soils of the coast of Piauí, aiming at the isolation of black yeasts. The research was carried out with the dry sand group collected from four beaches along the coast of Piauí and the soil of the Delta of the River Parnaíba, in the dry and rainy periods. Two fractions of sediment and sand were mixed in supplemented peptone water chloramphenicol, and homogenized by vortexing, one of them being added with vegetable oil. Aliquots of the extract obtained from the sand of the first fraction were cultivated in Sabouraud Dextrose Agar and in Potato Dextrose Agar, which were incubated until the appearance of dark colored colonies, in addition to being inoculated in CHROMagar® to count Candida spp. In addition, aliquots of the second fraction were inoculated into Mycobio Agar, and later analyzed for the presence of black colonies. The tests were carried out at the Laboratory of the Group for Advanced Studies in Medical Mycology, at the Federal University of Delta do Parnaíba. The region that obtained the highest total count of colonies in the dry period was the Parnaíba Delta. During this same period, an urban area of Atalaia beach and an urban and non-urban area of Pedra do Sal were the only ones obtained from black yeast counts. The beaches of Coqueiro, Vila Itaqui, Barrinha, Barra Grande and the Delta do Parnaíba obtained black fungus counts in the dry period. During the rainy season, the non-urban area of Coqueiro beach had the highest total count of colonies, and all beaches, except Vila Itaqui and Barrinha, had black yeast counts. It was observed that the highest counts are found in urbanized regions and during the rainy season. So, it is clear that, as the population of fungi in the sand on the coast of Piauí is sensitive to local urbanization, there is a need for long-term monitoring, since it can indicate which places are most affected by urbanization and that such microorganisms are of great clinical importance.