Biotechnological potential of marine invertebrate-associated bacteria with antibacterial activity against aquaculture and human pathogens

Marine invertebrates harbor diverse bacterial communities that contribute to host defense by producing antibacterial compounds. In this study, 258 cultivable bacterial isolates from corals (Porites panamensis, P. lobata), the sea urchin Echinometra vanbrunti, and the ctenophore Mnemiopsis leidyi were screened against aquaculture and human pathogens. 14% (37 isolates) exhibited antibacterial activity, predominantly from E. vanbrunti and M. leidyi. Multiple assays revealed strong, broad-spectrum inhibition, particularly against aquaculture pathogens such as Listonella anguillarum, Photobacterium damselae, and Vibrio parahaemolyticus, whereas human pathogens showed limited sensitivity. Notably, isolates MT26 and MT43 displayed the widest inhibitory spectra, and EV78 and MM7 demonstrated high inhibition rates in growth assays. Taxonomic analysis showed that Bacillus was the dominant genus (65%), followed by Vibrio and Pseudoalteromonas. These findings highlight marine invertebrate-associated bacteria as promising sources of bioactive compounds with potential applications in aquaculture and biotechnology.