Proteomic Analysis of Extracellular Membrane Vesicles of Bacteroides Fragilis Under Antibiotic Stress

The high antibiotic resistance of Bacteroides fragilis and its ability to combine symbiosis with pathogenicity in the human body make this species a key model for studying the bacterial stress response. Outer membrane vesicles (OMVs), secreted by Gram-negative bacteria, play a key role in intercellular communication, pathogenesis, and adaptation to antibiotics. In this study, we performed a proteomic analysis of B. fragilis OMVs exposed to meropenem using LC-MS/MS and label-free quantification (LFQ). Nineteen differentially expressed proteins were identified, belonging to the main functional groups: enzymes of amino acid and carbohydrate metabolism, antioxidant defense proteins, replication and translation factors, and methyltransferases. Taken together, these changes reflect a redistribution of metabolic fluxes toward maintaining energy balance and antioxidant defense under antibiotic stress. Thus, the proteomic profile of B. fragilis OMVs demonstrates their significant role in the mechanisms of bacterial survival and resistance, and also highlights their potential involvement in pathogenesis.