Production biomolecule with inhibitory activity against Gram-negative bacteria isolated from faeces of broilers and swine

The aim of this study was to investigate the potential of lactic acid bacteria, bacilli and yeasts isolates to produce antimicrobial substances, especially against Gram-negative bacteria isolated from the animal faeces, searching for a new alternative to control the enteritis diseases in animal health. Evaluations were performed by microdilution in broth using crude extract obtained from the cultivation of 272 strains against Escherichia coli, S. Typhimurium, S. Enteritidis and Pseudomonas aeruginosa. Thirty-five lactic acid bacteria presented some antimicrobial action. One Lactobacillus isolate, named FLPB-1, was selected to studies the kinetics of the production. An important increase in the production was obtained when the producer strain had cell-to-cell contact with a Gram-positive inducer culture. Maximal production of antimicrobial compounds was obtained in the beginning of stationary phase and the addition of urea in the medium increased the inhibition rate.