Glaesserella parasuis (GPS) infection leads to significant economic losses in livestock, with antibiotic resistance exacerbating the issue. The lengthy development cycle of new drugs further complicates timely intervention. Neuraminidase, a virulence factor of GPS, plays a critical role in infection progression. This study presents PSA-Gly-TD, a dual-responsive nanomicelle drug delivery system designed to target neuraminidase and pH variations, offering a solution to the problem of drug-resistant GPS infections. By covalently linking polysialic acid with Tildipirosin, nanoparticles with excellent dispersibility, stability, and a drug encapsulation efficiency of 99.27 % were synthesized. The system demonstrated a particle size of 64.75 nm, accelerated drug release in pathological conditions, and significantly enhanced cellular uptake-nearly three times higher than Tildipirosin alone while maintaining cell viability above 90 %. PSA-Gly-TD preserved the antibacterial efficacy of Tildipirosin and exhibited superior bactericidal activity against drug-resistant GPS strains. In animal models, PSA-Gly-TD showed a stable metabolic profile, reduced tissue damage, and avoided hemolysis, making it a safe and effective option for treating drug-resistant bacterial infections. These results underscore PSA-Gly-TD as a promising therapeutic agent, offering an innovative approach to combating antimicrobial resistance in veterinary medicine and addressing critical challenges in livestock health.
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