<p>As core microbiota in the intestine, <i>Veillonella</i> and <i>Lactobacillus</i> regulate the dynamic balance of lactic acid and short-chain fatty acids (SCFAs), and maintain intestinal homeostasis through synergistic metabolism. This study investigated the synergistic metabolism of <i>Veillonella ratti</i> (<i>V. ratti</i>) and <i>Lactobacillus acidophilus</i> (LA-85), and evaluated their combined protective effects against Enterohemorrhagic <i>Escherichia coli</i> O157:H7 (EHEC O157:H7) infection using a piglet intestinal ligation model. Mono-cultures and co-culture were conducted using the modified medium. During cultivation, the changes in viable counts, OD₆₀₀, pH, lactic acid, glucose, and SCFAs were monitored, as well as the effects on the expression of EHEC virulence genes. In the piglet intestinal ligation experiments, histological examinations, virulence gene detection, and microbiota analysis were performed on different ligated intestinal segments. In the modified medium, co-culture significantly increased the viable counts, OD₆₀₀, and SCFAs production, compared with mono-cultures. Co-culture suppressed the expression of EHEC virulence genes in vitro. In the piglet intestinal ligation experiments, combined administration of <i>V. ratti</i> and LA-85 ameliorated EHEC-induced intestinal inflammation, inhibited the formation of attaching and effacing lesions, and significantly down-regulated the expression of EHEC O157:H7 virulence genes. Furthermore, all the ligated segments exhibited obvious inflammation and Proteobacteria expansion. The intervention altered the ligation segments’ microbiota composition. These findings demonstrate that <i>V. ratti</i> and LA-85 synergistically inhibit EHEC O157:H7 infection. The underlying mechanism involves suppressing virulence gene expression in the pathogen and inhibiting the attaching and effacing lesions formation. This study demonstrates the potential application value of this combined probiotic strategy.</p>