effects of postbiotics derived from lactobacillus plantarum and bifidobacterium bifidum on biofilm formation and virulence gene expression of enterococcus faecalis

Background : enterococcus faecalis is an opportunistic pathogen capable of forming biofilms and developing antibiotic resistance, which complicates infection treatment. objectives :this study investigates the effect of postbiotics derived from lactobacillus plantarum and bifidobacterium bifidum on biofilm formation and virulence gene expression in e. faecalis. methods :in the present study, standard strains of l. plantarum atcc 8014, b. bifidum atcc 15696, and e. faecalis atcc 29212 were used. postbiotics/cell-free supernatants (cfss) were prepared from probiotics and added to e. faecalis. the contents of the obtained postbiotics were evaluated by gc-ms. biofilm formation was examined using the microtiter plate method, and the expression of endocarditis- and biofilm-associated pilus a (ebpa), enterococcal fibronectin-binding antigen a (efaa), aggregation substance (asa), and adhesin to collagen of enterococcus (ace) genes was assessed by real-time (rt)-pcr. results :the cfss significantly reduced biofilm formation in a dose-dependent manner. bifidobacterium bifidum cfss at 20, 10, and 5 mg/ml significantly decreased biofilm formation. similarly, l. plantarum cfss at 20 and 10 mg/ml showed a significant inhibitory effect. the qrt-pcr analysis revealed that l. plantarum cfss downregulated efaa, asa, and ace genes but had no effect on the ebpa gene. conversely, b. bifidum cfss reduced ebpa and ace gene expression but did not significantly alter efaa and asa genes. conclusions :these findings suggest that postbiotics may help reduce the pathogenicity of e. faecalis, particularly in preventing infections caused by e. faecalis.