Probiotic candidate strains from sow's milk show antimicrobial activity against multidrug-resistant Escherichia coli

Lactic acid bacteria (LAB) have been the subject of increasing interest in scientific research due to their broad spectrum of applications in human and animal health. In this research, the safety and functionality of LAB, with antimicrobial activity against two strains of Escherichia coli, isolated from sow's milk was evaluated. Five (5) presumptive LAB strains with high antimicrobial activity were molecularly identified. These strains belonged to the genera Lactiplantibacillus and Pediococcus, with percentages of identity ranging from 97% to 100%. These LAB were evaluated for safety (i.e., hemolytic capacity and antibiotic resistance) and functional (i.e., resistance to gastric and intestinal juices, ability to adhere to the Caco-2 cell line, hydrophobicity, and auto-aggregation) characteristics. Lactiplantibacillus plantarum (B10, 99.9% identity - MT544853) was identified and had a marked probiotic capacity due to its outstanding antimicrobial activity; its resistance to simulated gastrointestinal tract conditions, retaining viability up to 10⁸ CFU/mL after 4 h of exposure; roughly 3 % ability to adhere to intestinal cells; and the lowest antibiotic resistance capacity. The identified L. plantarum strain has potential for use in the prevention and control of diseases, especially those caused by E. coli strains with multiple antibiotic resistance. These findings contribute to the development of effective probiotics for the prevention of gastrointestinal diseases in pig production and, potentially, for human health applications, aligning with the One Health approach.