Study on the Non-Target Metabolomics Effects of Tylosin on Pasteurella multocida

Pasteurella multocida (P. multocida) is not only the core pathogen of bovine respiratory disease (BRDC) but also a significant zoonotic agent, posing a dual threat to global animal husbandry and public health. This study utilized untargeted metabolomics to systematically dissect the metabolic regulatory network of P. multocida in response to tylosin within a One Health framework. The results revealed significant "defense-growth" metabolic reprogramming: activation of amino sugar and nucleotide sugar pathways (e.g., CDP-glucose) indicated cell wall remodeling, while directional shifts in the phenylalanine-tyrosine network directed flux toward defensive secondary metabolites. Concurrently, amino acid disorders and the overactivation of the ABC transporter system exacerbated an internal energy crisis, characterized by a shift from respiration to glycolysis, ATP depletion, and ROS accumulation. SEM observations confirmed membrane integrity disruption and cytoplasmic leakage. Crucially, this metabolic stress and the transition into a "persister-like" dormant state are closely linked to the adaptive expression of antimicrobial resistance (AMR) genes. Under the selective pressure of tylosin, these metabolic perturbations may facilitate the emergence and horizontal transfer of resistance determinants, which can circulate through the animal-human-environment interface. By revealing the metabolic physiological basis of tylosin's action and its role in inducing bacterial tolerance, this study provides critical theoretical insights for antimicrobial stewardship, aiming to mitigate the risk of AMR transmission and preserve the efficacy of macrolides for both veterinary and human medicine.