| Congresso Brasileiro de Microbiologia 2023 | Resumo: 970-1 | ||||
Resumo:The fungus Batrachochytrium dendrobatidis (Bd) is chytridiomycosis pathogen, a highly virulent disease that has led to the decline and extinction threat for hundreds of amphibian species. In the face of this serious threat, conservation strategies to protect the affected species are of utmost importance.
In addition to the amphibians' skin, the foam nests of anurans also harbor unique microbiota in terms of function and composition. These structures represent a reproductive strategy used by some amphibian species to deposit their eggs. Remarkably, these nests show promising potential for isolating bacteria capable of inhibiting Bd from the moment of egg hatching, providing crucial initial protection.
Thus, the objective of this study is to evaluate the inhibition potential of bacterial isolates obtained from foam nests of Adenomera hylaedactyla, Leptodactylus vastus, and Physalaemus cuvieri species against the pathogen Batrachochytrium dendrobatidis, as well as the environmental safety of these strains through hemolytic activity testing. These assessments are fundamental to understanding the contribution of foam nest microbiota to the protection and survival of amphibians against chytridiomycosis, which may pave the way for the development of more effective and targeted conservation strategies.
To evaluate the anti-Bd activity, assays were conducted on solid medium, where cultures of the isolates were inoculated on agar plates containing Bd, and on liquid medium, where co-cultures of Bd zoospores and bacterial cultures were filtered to obtain cell-free supernatants (CFS). The CFS were added to Bd cultures in 96-well plates to analyze the inhibition of the fungus.
Regarding hemolytic activity, cultures of each isolate were inoculated on blood agar medium. Among the 183 isolates on solid medium, 54 showed anti-Bd activity. However, when testing 50 of these isolates in 96-well plates, variations in results were observed, ranging from facilitation to high inhibition of Bd growth. Additionally, 111 isolates showed no hemolytic activity, which is encouraging considering that hemolytic activity can be a potential virulence factor.
Five isolates (Serratia sp. A7, B8 - unidentified genus, Microbacterium sp. L6, Chryseobacterium sp. L15, and Pseudomonas sp. P137) demonstrated inhibitory activity in both assays and showed no hemolytic activity. These results suggest that foam nests may harbor bacteria with potential to be used as probiotics in the treatment of chytridiomycosis, but further studies are needed to confirm their safety and efficacy.
Palavras-chave: Chytridiomycosis, Foam nests, Hemolytic activity Agência de fomento:CNPq | |||||