Desenvolvimento de soluções biotecnológicas antiparasitárias voltadas ao controle Neoechinorhynchus buttnerae a partir de bactérias quitinolíticas oriundas de sedimentos dos rios amazônicos

Abstract

Aquaculture is among the fastest-growing animal food production sectors globally, but its expansion is heavily constrained by the occurrence of parasitic diseases. In Brazil, the farming of tambaqui (Colossoma macropomum) is threatened by acanthocephalosis, caused by the intestinal parasite Neoechinorhynchus buttnerae. This disease currently lacks fully effective and environmentally safe therapies, making it one of the main sanitary obstacles to the sustainable expansion of national fish farming. To address this gap, the present study investigated the biotechnological potential of 37 chitinolytic bacterial strains isolated from Amazon basin sediments, integrating complementary approaches of in vitro phenotypic screening and in silico genomic mining. The results revealed that 18 isolates exhibited activity against the acanthocephalan N. buttnerae, with Streptomyces amazonensis strain MAD 27 standing out for its high efficiency, inducing 100% mortality in N. buttnerae within just 2 to 5 hours, a performance equivalent to the positive control (levamisole hydrochloride). Comparative analysis with extracts confirmed the presence of bioactive secondary metabolites, suggesting a multifaceted mechanism of action that may involve enzymatic activity and compound release. Comparative tests with live and autoclaved cultures of the most effective strains demonstrated that the activity is thermolabile and dependent on the integrity and/or metabolic activity of the microorganism. Genomic analysis of the most promising strains provided the molecular basis for their observed efficacy, revealing Biosynthetic Gene Clusters (BGCs) responsible for producing metabolites already known to possess antiparasitic activity, including Polyketides (such as Antimycin, a potent mitochondrial inhibitor) and Non-Ribosomal Peptides (such as Actinomycin D, a DNA/RNA inhibitor). The presence of these BGCs suggests that the high lethality observed may be mediated by mechanisms of action targeting vital parasite functions. This work establishes Streptomyces amazonensis strain MAD 27 as a prime candidate for the development of sustainable biotechnological solutions, either as a live culture biotherapeutic or as a source of novel drugs. The integrated phenotypic-genomic approach validates bacteria from river sediments as a reservoir of chemical diversity for parasitic control in aquaculture, offering an ecologically safer alternative to conventional treatments.