Evaluating the antimicrobial activity of Bacillus australimaris and Pseudoalteromonas sp. associated with the octocoral Leptogorgia alba Abstract

Abstract

Octocoral-associated bacterial assemblages provide them with defensive strategies through production of antimicrobial compounds, protecting against pathogenic microorganisms by avoiding colonization by other microorganisms. Due to the decrease in the discovery of new compounds in terrestrial environments, the potential of marine bacterial strains represents a source of novel bioactive compounds. Our objective was to evaluate the antimicrobial activity of the bacterial strains of Bacillus australimaris and those of Pseudoalteromonas sp. isolated from the octocoral Leptogorgia alba from shallow and mesophotic areas, to determine the degree of capacity they have to inhibit the growth of human and aquaculture pathogens, for which cross-streak tests, agar diffusion by drop, well diffusion, disk diffusion, growth on cellulose and polystyrene microplate were used. Antagonism of B. australimaris was evident towards pathogens Escherichia coli, Listonella anguillarum, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus iniae, and Vibrio campbellii. For its part, Pseudoalteromonas sp. prevented the development of the pathogens E. coli, L. anguillarum, L. monocytogenes, S. iniae, and V. campbellii. The results of this work show that bacteria associated with gorgonid organisms are a potential biotechnological resource in antimicrobial activity.