Lactobacillus johnsonii 1735 Confers Dual-Targeted Protection against Antimicrobial-Resistant aEPEC: Suppressing NleA Virulence and Activating EGFR/AKT Signaling to Attenuate Intestinal Epithelial Stress

Antimicrobial-resistant atypical enteropathogenic Escherichia coli (aEPEC), a pervasive foodborne pathogen in livestock, causes severe infections that are recalcitrant to conventional antibiotics. This challenge is exacerbated by its dual threat of multidrug resistance and the deployment of virulence effectors like NleA. Current probiotic solutions remain limited by single-target mechanisms that fail to disrupt the pathogen-host interplay. This study demonstrates that Lactobacillus johnsonii 1735 overcomed this limitation through a novel dual-pathway strategy simultaneously targeting pathogen virulence via NleA suppression and host signaling via EGFR/AKT activation, proposing a synergistic strategy against drug-resistant pathogens. In a murine model, pretreatment with the sow-derived probiotic L. johnsonii 1735 alleviated intestinal and hepatic damage, reduced aEPEC colonization, and restored gut microbiota homeostasis. In intestinal epithelial cells, the probiotic inhibited aEPEC-induced endoplasmic reticulum stress (ERS) and apoptosis, concurrently diminishing the virulence effector NleA during bacterial adhesion. Crucially, L. johnsonii 1735 activated the EGFR/AKT survival pathway, and siRNA-mediated EGFR silencing abolished its protective effects. These findings highlight the potential of agricultural-origin probiotics as novel biocontrol agents in the food chain. L. johnsonii 1735 presents a promising strategy to mitigate antimicrobial-resistant aEPEC infections in livestock, potentially enhancing animal health and contributing to food safety.