Microorganisms of the intestinal microbiota of Oncorhynchus mykiss produce antagonistic substances against bacteria contaminating food and causing disease in humans

The objective was to analyse the antibacterial ability of members of the intestinal microbiota of Oncorhynchus mykiss specimens on several bacterial target strains that contaminate food and cause disease in humans. Bacterial colonies from an intestinal portion of the 20 specimens of O. mykiss were obtained in different culture media. Several of the colonies showed antibacterial action on different target strains. The bacterial species with the highest antagonistic capacity were Hafnia alvei and Lactococcus lactis and the more susceptible target strains were Aeromonas hydrophila, Listeria monocytogenes and Escherichia coli. Moreover, it was shown that all the antibacterial substances were susceptible to the action of various proteolytic enzymes. The detection of substances of a proteinaceous nature, possibly bacteriocins produced by bacteria of the intestinal microbiota of O. mykiss, allows further study of these products to establish biotechnological developments in the area of health protection and food biopreservation.