P369 Aspergillus spp. in coastal environments with different salinity

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM Aspergillus is a fungus genus found in several environments due to its ubiquitous characteristic. The emergent antifungal resistance of these fungi and their relation with animal and human pathogens turned necessary a One Health approach, which unites animal, human and environmental health as one. In this context, the ocean can be an inhospitable environment in view of the high salinity and other variables like pH and temperature, however, Aspergillus spp. is reported as a pathogen of marine animals, and the ocean can be a reservoir and/or creator of resistant strains considering the unfavorable conditions found there.Objective: We aimed to evaluate the seasonal frequency of Aspergillus spp. In different coastal environments in southern Brazil.MethodsSamples of surface water were collected monthly from July 2021 to April 2022 at three coastal environments in the municipality of Rio Grande/RS. The locations were 1) Lagoonal system/Lagoa dos Patos (−32.0253°S, −52.1060°W); 2) Lagoon mouth (−32.1495°S, −52.1009°W) and 3) Sea/Cassino beach (−32.2066°S, −52.1738°W). Water samples (1000 ml) were collected in sterile bottles, refrigerated and cultured within 12 h. An adapted technique of filtering membrane (0.45 μm) culture by vacuum filtration system was performed. Briefly, after filtration, the membrane was transferred to a falcon tube with 10 mL of sterile saline and vortexed (3 min) for elution. Subsequently, the membrane was disposed of on Sabouraud-dextrose (SDA) plates with gentamicin and chloramphenicol (SDAGC). The resulting elution was centrifuged at 3500 rpm (3 min) and the precipitate (500 μL) was also cultured in duplicate by spreading on SDAGC plates. Plates were incubated at 30°C for 7 days, being evaluated daily for fungal growth. Aspergillus spp. were identified at section level by macro and micromorphological characteristics. The determination of the water salinity in the samples was performed with a YSI multiparameter (ProDSS).ResultsThe average salinity of the water samples (n = 10) was 18.57 PSU (SD = 14.58) at point 1 (Lagoon), 19.45 PSU (SD = 14.95) for the point 2 (Lagoon mouth), and 31.31 PSU (SD = 3.18) for point 3 (Sea). Aspergillus spp. Was isolated in 23%, 37%, and 40% of the samples at points 1, 2 and 3, respectively. A total of 30 isolates were obtained, being 13 section Fumigati, 10 Flavi, 6 Nigri, and 1 Terrei. In point 1 and 2, the Fumigati section predominated (57% and 54%, respectively). On the other hand, at point 3, section Flavi (41%) predominated, with Fumigati corresponding to just 25%.ConclusionAlthough pathogenic Aspergillus sections can be isolated from environments with distinct salinities, the section Fumigati seems to be less frequent in higher salinity places. Their antifungal susceptibility profile will be tested prospectively.