Baicalin-aluminum complexes inhibit growth and suppress virulence of enterotoxigenic Escherichia coli in vitro.

Enterotoxigenic Escherichia coli (ETEC) is the leading cause of diarrhea in piglets. With the restricted use of antibiotics, there is an urgent need to identify effective alternatives to control ETEC-induced diarrhea. This study aimed to investigate the effects of baicalin-aluminum (BA) complexes on ETEC growth, bacterial membrane permeability, enterotoxin release, and expression of virulence-related factors through dose-dependent growth inhibition assays, membrane permeability tests, ELISA-based toxin quantification, and qRT-PCR analysis of virulence factors (e.g., est, elt, faeG). We demonstrated that BA complexes significantly inhibited ETEC growth in a dose-dependent and increased membrane permeability. Additionally, BA complexes effectively reduced the secretion of enterotoxins and downregulated the expression of ETEC virulence-related factors. These findings suggest that BA complexes exert antibacterial effects by compromising membrane integrity and suppressing virulence-related pathways, though their precise molecular mechanisms require further investigation. In conclusion, BA complexes may serve as a promising antibiotic alternative for managing ETEC infections in piglets, offering a multi-targeted approach to inhibit bacterial viability and virulence.