Lactobacillus plantarum WCFS1 and Lactobacillus gasseri A237 as Therapeutic Candidates for Gut Pathogen Control: Inhibition of Escherichia coli

Abstract

The gut microbiome is a complex microbial ecosystem that requires a delicate balance to maintain host health homeostasis. Gut dysbiosis, characterized by reduced microbial diversity and shifts in the relative abundance of commensal and pathogenic species, is implicated in chronic conditions including ulcerative colitis, obesity and diabetes mellitus. Common gut pathogens include gram-negative Escherichia coli and gram-positive Staphylococcus aureus , both of which contribute to intestinal disease and systemic infection. Antibiotic therapies remain the standard of care for pathogenic infections; however, the rising threat of antibiotic resistance and the disruption of gut microbial homeostasis associated with antibiotic use warrants alternative therapeutic approaches. Probiotics represent a promising therapeutic strategy for restoring microbial balance by promoting beneficial bacteria while suppressing pathogenic activity, though additional evidence supporting strain-specific, anti-pathogenic properties is needed. This study evaluated the therapeutic potential of human-derived Lactobacillus plantarum WCFS1 and Lactobacillus gasseri A237 against the pathogenic activity of E. coli ATCC 25922 and S. aureus subsp. aureus ATCC 25923 via competitive adhesion and minimum inhibitory concentration assays. Overall, the probiotic strains demonstrated inhibition against pathogen activity, with greater effects observed against S. aureus , which prompted further evaluation of its biofilm formation and growth in the presence of probiotics. Notably, L. gasseri significantly reduced S. aureus adhesion to HT-29 intestinal epithelial cells by 55.70% ( p=0.009 ), while the reduction in E. coli adhesion (9.84%) was not statistically significant. Probiotic cell-free supernatants suppressed S. aureus growth by up to 95% and reduced biofilm formation in a concentration-dependent manner, with MIC achieved at a 1:4 dilution (12.25% v/v ) against both pathogens for all groups. Together, these findings demonstrate that L. plantarum WCFS1 and L. gasseri A237 exert anti-pathogenic effects against common human gut pathogens, supporting their potential as therapeutic candidates for the management of E. coli and S. aureus pathogens. This approach may also be used for other clinically relevant pathogenic species, warranting further investigation.