Metabolomic and Proteomic Profiling of the Antimicrobial Potentials from Lactobacillus johnsonii KD1 Cell-Free Supernatant against Foodborne Pathogenic Bacteria

ABSTRACT:

This study characterized functions and metabolic profiles of cell-free supernatants (CFS) from Lactobacillus johnsonii KD1 against three foodborne pathogens: the Gram-negative bacteria Vibrio parahaemolyticus 3HP and Salmonella enterica serovar Typhimurium LT2, and the Gram-positive bacterium Listeria monocytogenes 10403S. The minimum inhibitory concentration (MIC) at 25% CFS inhibited the growth of all tested pathogens.  At this concentration, the CFS exhibited bactericidal activity against both Gram-negative bacteria, while only bacteriostatic activity was observed against the Gram-positive bacterium. Neutralized CFS demonstrated that antimicrobial activity was pH-dependent, as the MIC increased to 50% CFS for V. parahaemolyticus and no inhibition was observed against S. Typhimurium. The stability of CFS at low temperature for 90 days has maintained antimicrobial activity with MIC from 12% to 25% against V. parahaemolyticus with bactericidal effects. Untargeted metabolomic profiling revealed numerous significant features, including 433 in positive ionization mode and 102 in negative mode.  Highly abundant metabolites in the positive mode were primarily classified as aminoglycosides, while the random forest analysis identified key discriminative metabolites from aminoglycosides, cardenolides and derivatives, and steroid esters.  In the negative mode, metabolites were mainly associated with probiotic metabolism, with 4-hydroxyphenyllactic acid identified as a potential biomarker contributing to inhibition of L. monocytogenes.  Strong correlations were observed among key metabolites. Proteomic analysis identified 24 proteins significantly secreted in the CFS from MRS media and the probiotic with glyceraldehyde-3-phosphate dehydrogenase, which served as a marker for L. johnsonii KD1 CFS.  These findings suggest that the probiotic CFS can be used to combat foodborne bacteria and its application as a biopreservative in the food industry.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse-phase, Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS14550 | MetaboLights | 2026-09-24

REPOSITORIES: MetaboLights