Directional and Strain-Specific Interaction Between Lactobacillus plantarum and Staphylococcus aureus

The interaction between <i>Lactobacillus plantarum</i> and <i>Staphylococcus aureus</i> strains FRI-1169 and MN8, two original isolated strains from menstrual toxic shock syndrome (mTSS) cases, is a key focus for developing non-antibiotic strategies to control <i>S. aureus</i>-related infections. While the antagonistic effects of <i>Lactobacilli</i> species on <i>S. aureus</i> through mechanisms like organic acid and bacteriocin production are known, the molecular dynamics of these interactions remain underexplored. This study employs a proteomic approach to analyze the interactions between <i>L. plantarum</i> WCFS1 and <i>S. aureus</i> strains, FRI-1169 and MN8, during co-culture. We profiled differentially expressed proteins (DEPs) found in the spent media and cytosols of both bacteria, revealing distinct directional and strain-specific responses. The findings demonstrate that <i>L. plantarum</i> exerts a more pronounced effect on <i>S. aureus</i>, with more DEPs and upregulated proteins, while <i>S. aureus</i> showed fewer DEPs and more downregulated proteins. These strain-specific interactions highlight the complex metabolic and regulatory adjustments between these bacterial species. This research provides valuable insights into the molecular mechanisms of <i>Lactobacillus-S. aureus</i> antagonism and underscores the potential of proteomic analysis as a powerful tool for studying bacterial dynamics in co-culture systems.