Broad‐Spectrum Antibacterial Activity of Postbiotic From <i>Lacticaseibacillus paracasei</i> BGP1 Against Multidrug‐Resistant Skin Wound Pathogens

The increasing problem of antibiotic resistance indicates the need for alternative therapeutic strategies for skin wound infections. While probiotics exhibit potential for developing such alternatives, the majority of antimicrobial studies focus on live cells or lysates and oral delivery. Notably, in dermatology, formulating products with live strains poses technical challenges due to stability issues in water-based systems. Postbiotics, substances made from probiotics, offer a promising, stable, and safe alternative. This study addresses the gap by evaluating the antibacterial potential of cell-free supernatants (CFSs) from six probiotic strains, with a specific focus on Lacticaseibacillus paracasei BGP1, against clinically relevant skin pathogens. CFSs were screened in vitro using agar well diffusion and broth microdilution assays against Staphylococcus aureus ATCC 25923, methicillin-resistant S. aureus (MRSA; UTMC 1442), Pseudomonas aeruginosa ATCC 27853, and P. aeruginosa PAO1. GC-MS analysis was used to identify bioactive compounds in the most promising CFS. Among the tested strains, BGP1 demonstrated both consistent inhibitory (MIC: 6.25 mg/mL) and bactericidal (MBC: 12.5 mg/mL) effects. GC-MS analysis identified palmitic acid (33.24%) and stearic acid (46.45%) as dominant bioactive compounds. These findings provide novel evidence that postbiotic metabolites from L. paracasei BGP1 represent a promising, broad-spectrum, stable, and nonliving candidate to conventional therapies for antibiotic-resistant skin wound infections. Further in vivo research is needed to evaluate their therapeutic potential and formulation in clinical settings.