Quantitative proteomics reveals the mechanism of silver nanoparticles against multidrug-resistant Pseudomonas aeruginosa biofilm.

The decline of clinical effective antibiotics has made it necessary to develop more effective antimicrobial agents, especially for refractory biofilm-related infections. Silver nanoparticles (AgNPs) are a new type of antimicrobial agent that can eradicate biofilms and reduce bacterial resistance, but its anti-biofilm mechanism has not been elucidated. In this study, we investigated the molecular mechanism of AgNPs against multidrug-resistant Pseudomonas aeruginosa by means of anti-biofilm tests, scanning electron microscope (SEM), and the Tandem Mass Tag (TMT)-labeled quantitative proteomics. Results of anti-biofilm demonstrated that AgNPs inhibited the formation of P. aeruginosa biofilm and disrupted its preformed biofilm. SEM showed that when exposed to AgNPs, the structure of P. aeruginosa biofilm was destroyed, along with significant reduction of its biomass. TMT-labeled quantitative proteomic analysis revealed that that AgNPs could defeat P. aeruginosa biofilm in multiple ways by inhibiting its adhesion and motility, stimulating strong oxidative stress response, destroying iron homeostasis, blocking aerobic and anaerobic respirations, and affecting quorum sensing (QS) systems. Our findings offer a new insight into clarifying the mechanism of AgNPs against biofilm, thus provide a theoretical basis for its clinical application.