A Multifunctional Nanobooster to Restore Ceftazidime Susceptibility in Mucoid Pseudomonas aeruginosa

Abstract

Mucoid Pseudomonas aeruginosa (m.PAE) presents a major clinical challenge due to its high resistance to ceftazidime (CAZ), a cornerstone antibiotic. This resistance is orchestrated through three barriers, including the formation of an alginate-rich mucoid biofilm that limits drug penetration, upregulated efflux pumps such as MexXY-OprM that reduce intracellular CAZ accumulation, and expression of β-lactamases that hydrolyze CAZ. To address these barriers simultaneously, we engineered a multifunctional nanoagonist termed A/C-pAg₃PO₄, which integrates a silver phosphate nanoparticle (NAg₃PO₄) core for bacterial disruption, a carboxyl-PEG coating (pAg₃PO₄) to improve biofilm penetration, and dual co-loading of avibactam (AVB) to inhibit β-lactamase and carbonyl cyanide m-chlorophenylhydrazone (CCCP) to block efflux pumps. In vitro, A/C-pAg₃PO₄ showed potent antibacterial efficacy, penetrated mucoid biofilms efficiently, and restored bacterial susceptibility via metabolic reprogramming. In murine models of acute pneumonia and lethal sepsis, it markedly reduced bacterial load, mitigated inflammatory damage, and achieved complete survival with no evident toxicity. Our work thus provides a promising strategy to overcome m.PAE resistance to CAZ by concurrently targeting its key defensive mechanisms.