| Congresso Brasileiro de Microbiologia 2023 | Resumo: 988-1 | ||||
Resumo:Brazil brings together some of the world’s largest iron formations that have become a
major target of study in recente years. Thus, environmental bacterial, specifically from
cave environments, become an importante source for the development of bioactive
compounds due to their ability to adapt to extremophile environments. Knowledge about
the microbial potential of these cave microorganisms gives us a starting point for the
development of new antimicrobial compounds. Therefore, the objective of this research
was to determine the antimicrobial resistance profile of bacterial isolates from iron caves
in Serra da Bocaina, located in the Campos Ferruginosos National Park, in the
municipality of Canaă dos Carajás, PA, Brazil. For this, 51 bacteria isolated from the soil
of iron caves selected from two caves (GEM-1462 and GEM-1423) were evaluated for
resistance to 12 commercial antimicrobials, namely Amoxicillin (10 µg), Nalidixic Acid
(30 µg), Ampicillin (10 µg), Ciprofloxacin (5 µg), Chloramphenicol (30 µg),
Streptomycin (10 µg) Imipenem (10 µg), Gentamicin (10 µg), Norfloxacin (10 µg),
Trimethoprim (5 µg), Sulfazotrim (25 µg) and Tetracycline (30 µg). Bacteria were
isolated from the surfacce layer of each cave, in the first 10 cm in three diferente zones:
photic zone, dysphotic zone and aphotic zone. The collection took place under the license
of the Biodiversity Authorization and Information System (SISBIO) nş 79255-1 in the
dry and rainy season, a period that covers the months of September 2022 and March 2023,
respectively. To assess antimicrobial resistance, the Kirby-Bauer disk diffusion technique
was used, as described by Bauer et al. in 1966. The resistance profile was then analyzed
following the guidelines established by the Clinical and Laboratory Standards Institute
(CLSI) in 2017. The results revealed diferente resistance patterns, bringing valuable
information about the dynamics of bactéria in caves under diferente environmental
conditions. It was observed that 68.7% of bactéria in the dry season were resistant to at
least 2 antimicrobials, while in the rainy season the percentage of resistance was 92.8%.
In general, approximately 80% of bacteria exhibited resistance to at least two
antimicrobials. Notably, both Ampicillin and Amoxicillin, belonging to the penicillin
class, stood out as antimicrobials to which bactéria demonstrated significant resistance,
in addition to the previously mentioned high resistance to Trimethoprim. On the other
hand, it was observed that the quinolones (Ciprofloxacin and Norfloxacin) and the
aminoglycoside (Gentamicin) maintained their constant effectiveness throughout the
diferente sampling seasons. This suggests that these bactéria showed less pronounced or
impactful resistance to these antimicrobials over the study period. Palavras-chave: antimicrobials , iron caves , resistance Agęncia de fomento:Unioeste, IABS, Instituto Tecnológico do Vale | |||||