Screening, probiotic properties, and inhibition mechanism of a Lactobacillus antagonistic to Listeria monocytogenes.

Abstract

Listeria monocytogenes is one of the most lethal foodborne pathogens, and there is a lack of microorganisms that can strongly inhibit its growth. Safe lactic acid bacteria with probiotic and antibacterial properties are ideal sources of antagonistic bacteria. This study isolated a strain of Lactobacillus plantarum 4-10 that completely killed L. monocytogenes from northeastern Chinese sauerkraut. Probiotic characterization revealed broad-spectrum bacterial inhibition, antagonizing 16 Gram-positive, Gram-negative, and fungal species. After tolerance to simulated intestinal and gastric fluids, the survival rate was >45 %. L. plantarum 4-10 was sensitive to chloramphenicol, doxycycline, erythromycin, and tetracycline, and exhibited good hydrophobicity, auto-aggregation, and co-aggregation. It could disrupt the cell structure when co-cultured with L. monocytogenes and act as a lethal agent within 15 h. Through transcriptomic analysis and validation experiments, we found that L. plantarum 4-10 could inhibit the expression of L. monocytogenes membrane transport-related genes by producing bacteriocins, thus disrupting the cell membrane structure and inhibiting the growth, metabolic viability, and biofilm formation of L. monocytogenes in a short time. In conclusion, L. plantarum 4-10 has good probiotic properties and antibacterial effects and shows excellent research and application prospects as a natural bacteriostat.