Integrated metabolomic and transcriptomic analyses of the synergistic effect of polymyxin B/DDC combination against Pseudomonas aeruginosa

Background The resistance of Gram-negative bacteria to polymyxin B has spread. In order to rescue the failure of polymyxin B treatment, our study integrated the whole genome, metabolomics, and transcriptomics for the first time to clarify the Synergistic killing mechanism of polymyxin/DDC combination against chromosomally encoded polymyxin B-resistant Pseudomonas aeruginosa. Methods De novo genome sequencing was employed to acquire the complete genome sequence information of P. aeruginosa P2550. Subsequently, the metabolome and transcriptome of P. aeruginosa P2550 exposed to polymyxin B and DDC alone, or their combination were investigated using liquid chromatography-mass spectrometry and RNA sequencing analysis to identify significant changes. The iPath tool was utilized to map the genes and metabolites that displayed notable alterations in response to the combination at 0.5h, 1h, 2h, and 4h, providing comprehensive analysis and visual representation of the metabolic network of Pseudomonas aeruginosa P2550. Results In vitro antibacterial efficacy studies have shown that the combination has a killing effect on P. aeruginosa P2550 and can inhibit the formation of biofilm. Multi-omics comprehensive analysis showed that the combination inhibited the LPS modification pathway, prevented biofilm formation, and disrupted arginine biosynthesis, TCA cycle, nucleotide and membrane-associated lipid metabolism pathways. In a mouse infection model, the combination increased survival rates and bacterial clearance from organs. Conclusion This study highlights the great potential of polymyxin/DDC combinations in synergistic bacterial killing mechanisms and provides a theoretical basis for antibiotic adjuvants to improve antibiotic efficacy and mitigate bacterial antibiotic resistance.