Aquaculture pond is a rich source of Streptomyces spp. with promising potential for developing quorum sensing manipulating probiotics

Applying quorum-quenching (QQ) probiotics is a promising non-antibiotic-based strategy for sustainable aquaculture. In this study, a total of fifty-two <i>Streptomyces </i>strains were isolated and identified from aquaculture pond sediment and intestines of fish collected in the Panyu District of Guangzhou, China. Half of the isolated strains exhibited varying degrees of antagonistic activity against a variety of pathogenic bacteria in aquaculture, including <i>Aeromonas hydrophila</i>, <i>Pseudomonas aeruginosa</i>, <i>Vibrio parahemolyticus</i>, <i>Staphylococcus aureus</i>, and <i>Streptococcus agalactiae</i>. Among the forty-four strains whose genome was successfully isolated, 39 (∼90 %) were demonstrated carrying AHL-acylase encoding genes by PCR, indicating the natural and ubiquitous potential of <i>Streptomyces </i>spp. in degrading quorum sensing (QS) signals. Nine strains, S7, S10, S11, S25, TI9, TI11, TI15, DI5, and DI9, showed clear QS inhibition (QSI) activity in agar well diffusion assays by applying <i>Agrobacterium tumefaciens </i>A136 and <i>Chromobacterium violaceum </i>CV026 as biosensors. An RT-PCR analysis demonstrated the repressed expression of a variety of virulence genes in <i>P. aeruginosa </i>when co-cultured with strain S25. The results of this study demonstrate the favorable probiotic potential of <i>Streptomyces </i>spp. Isolated from the aquaculture environment, particularly in their ubiquitous QSI ability. These strains serve as promising QQ probiotic candidates and may contribute to developing novel eco-friendly anti-virulence therapy strategies for aquaculture. Copyright © 2025. Published by Elsevier B.V.