Avaliação de Fatores de Pagenicidade de Fungos Negros Oriundos da Areia da Praia da Pedra do Sal, Litoral do Piauí

Abstract

Black fungi are a group of melanized, pleomorphic and ubiquitous ascomycetes, despite being found with greater frequency in regions with a tropical and subtropical climate. Embora is not pathogenetic, some species are associated with mycoses of great clinical importance, such as cromoblastomicose, pheohifomicose and or eumycetoma, affecting immunocompromised and immunocompetent individuals. Com isso, to investigate the presence of microorganisms in locations with a large flow of people and of interest in public health. Located in the municipality of Parnaíba, Praia da Pedra do Sal is of great importance for tourism and the performance of labor activities such as fishing or shellfish, as well as for sports practice. Valuing local area is extremely important, considering that no work has been carried out on this theme. Also, this study has the objective of characterizing the pathogenicity of isolated black fungi from samples of the Praia da Pedra do Sal area, by means of thermotolerance analysis, halotolerance, and the production of DNAse and urease. To obtain two isolates, peptone water supplemented with chloramphenicol was added in samples of areia, being inoculated aliquots of the solution processed in Sabouraud Dextrose Agar; Ágar Mycobio and Ágar Batata Dextrose. In a thermotolerance analysis, the isolates grown in Ágar Sabouraud and incubated at a temperature of 37 ° C for 15 days. Growth was classified as the last when the area occupied by the colony was greater than 20mm, intermediate when it was approximately 20mm and lower when it occupied an area less than 20mm. A halotolerância was investigated in liquid medium (Sabouraud Broth) 3disposited in 96-well plates, with NaCl concentrations: 2.5%; 5%; 7.5%; 10%; 15% and 20%. For the evaluation of the production of DNase and urease foram used, respectively, DNase Test Agar plates supplemented with toluidine blue dye and ureia-agar-base medium, with each isolate being inoculated and incubated at 30 ̊C for 15 days. All the tests were carried out in duplicate. Forms obtained and tested 29 isolates from Praia da Pedra do Sal, two quais 15 (51.7%) remain with a leveduriform appearance and 14 (48.3%) demonstrate dimorphism (yeast-type fungi). All isolated cresceram at a temperature of 37 ° C in a period of 15 days, with 20 (69%) as the optimum growth, 4 (13.8%) as intermediate growth and 5 (17.2%) as low growth. With a halotolerance assessment, all isolates are capable of increasing to 20% NaCl, at a higher concentration tested. Regarding the production of enzymes, 10 isolates (34.5%) were positive for urease production, while only 2 (6.9%) isolated demonstrated the ability to hydrolyze DNA. Therefore, it is observed that the isolated black fungi of the Pedra do Sal beach area can express virulence factors and show a high non-environmental persistence capacity. We certify that these results may help us not understand the questions regarding the inclination of these fungi to cause infections in humans and animals that circulate in coastal regions, since, at present, the literature lacks studies that validate this correlation.