TMT-based quantitative proteomics analysis reveals the inhibitory mechanism of CD-g-CS against the biofilm formation of Staphylococcus xylosus

Chitosan-grafted β-cyclodextrin (CD-g-CS) serves as an excipient combining drug delivery capacity with antimicrobial activity. Previous studies have demonstrated that the CD-g-CS nanoformulations have significant inhibitory effects on bacterial biofilms, although the mechanism of action remains unclear. Consequently, the present study used tandem mass tag (TMT)-based quantitative proteomics coupled with quantitative PCR (qPCR) to investigate the mechanism underlying CD-g-CS-mediated inhibition of Staphylococcus xylosus (S. xylosus) biofilm formation at the protein level. The results showed that 903 proteins were identified to be altered in S. xylosus treated with CD-g-CS, of which 430 were down-regulated and 500 were up-regulated. Bioinformatics analysis revealed that these differentially expressed proteins (DEPs) have different molecular functions and are involved in different molecular pathways. CD-g-CS affected the functional pathways of S. xylosus in terms of ribosomes, phosphotransferase system (PTS), tricarboxylic acid (TCA) cycle, and nitrate respiration. These pathways affected the stability and morphology of biofilms, which in turn interfere with biofilm formation. These results provide a critical excipients for future development of anti-biofilm pharmaceutical formulations, offering novel solutions to combat biofilm infections.