Avaliação da atividade antimicrobiana de linhagens de Pseudomonas isoladas de ninhos de espumas de rãs

Abstract

Anurans have developed various tactics for growth and reproduction, one of which involves foam nests—biostructures of rich composition housing a distinctive microbiota that protects eggs and provides a habitat for tadpoles post-hatching. Anurans exhibit considerable biotechnological potential owing to their capacity to produce antimicrobial biomolecules. However, bacteria residing in these nests have been minimally explored concerning their efficacy in producing antimicrobial compounds and their potential applications in medicine or agriculture. The Pseudomonas genus is prevalent in these nests, showcasing high biotechnological potential, notably in the production of antimicrobial compounds. This study aimed to assess the antimicrobial potential of Pseudomonas strains isolated from foam nests of the frogs Leptodactylus vastus, Adenomera hylaedactyla, and Phylasaemus cuvieri in the state of Ceará. Additionally, the genomic analysis of one of the most promising strains was conducted. Six Pseudomonas strains isolated from frog foam nests were tested against phytopathogenic filamentous fungi Fusarium oxysporum and Rhizoctonia solani. Two strains were assessed against Gram-positive and Gram-negative human pathogenic bacteria such as Staphylococcus aureus and Salmonella enterica. The most promising strain in the antifungal assay had its genome sequenced, assembled, and annotated, with a focus on identifying "housekeeping" genes, antifungal genes, and genes associated with virulence and pathogenicity. Among the six strains studied, one exhibited antifungal activity, and two displayed antibacterial activity. Genomic analysis of the B8 strain identified it as Pseudomonas putida based on 16S rDNA, gyrB, and rpoB genes. Thus, Pseudomonas strains from foam nests demonstrated antimicrobial compound production, providing avenues for future investigations into their ecological characteristics and biotechnological potential.