Metabolomics Study of the Synergistic Killing of Polymyxin B in Combination with Amikacin against Polymyxin-Susceptible and -Resistant Pseudomonas aeruginosa

Antimicrob Agents Chemother. 2019 Dec 20;64(1):e01587-19. doi: 10.1128/AAC.01587-19. Print 2019 Dec 20.


In the present study, we employed untargeted metabolomics to investigate the synergistic killing mechanism of polymyxin B in combination with an aminoglycoside, amikacin, against a polymyxin-susceptible isolate of Pseudomonas aeruginosa, FADDI-PA111 (MIC = 2 mg/liter for both polymyxin B and amikacin), and a polymyxin-resistant Liverpool epidemic strain (LES), LESB58 (the corresponding MIC for both polymyxin B and amikacin is 16 mg/liter). The metabolites were extracted 15 min, 1 h, and 4 h following treatment with polymyxin B alone (2 mg/liter for FADDI-PA111; 4 mg/liter for LESB58), amikacin alone (2 mg/liter), and both in combination and analyzed using liquid chromatography-mass spectrometry (LC-MS). At 15 min and 1 h, polymyxin B alone induced significant perturbations in glycerophospholipid and fatty acid metabolism pathways in FADDI-PA111 and, to a lesser extent, in LESB58. Amikacin alone at 1 and 4 h induced significant perturbations in peptide and amino acid metabolism, which is in line with the mode of action of aminoglycosides. Pathway analysis of FADDI-PA111 revealed that the synergistic effect of the combination was largely due to the inhibition of cell envelope biogenesis, which was driven initially by polymyxin B via suppression of key metabolites involved in lipopolysaccharide, peptidoglycan, and membrane lipids (15 min and 1 h) and later by amikacin (4 h). Overall, these novel findings demonstrate that the disruption of cell envelope biogenesis and central carbohydrate metabolism, decreased levels of amino sugars, and a downregulated nucleotide pool are the metabolic pathways associated with the synergistic killing of the polymyxin-amikacin combination against P. aeruginosa This mechanistic study might help optimize synergistic polymyxin B combinations in the clinical setting.

Keywords: Pseudomonas aeruginosa; amikacin; metabolomics; polymyxin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amikacin / pharmacology*
  • Anti-Bacterial Agents / pharmacology*
  • Chromatography, Liquid
  • Lipopolysaccharides / pharmacology
  • Mass Spectrometry
  • Metabolomics / methods
  • Microbial Sensitivity Tests
  • Peptidoglycan / pharmacology
  • Polymyxin B / pharmacology*
  • Polymyxins / pharmacology*
  • Pseudomonas aeruginosa / drug effects*


  • Anti-Bacterial Agents
  • Lipopolysaccharides
  • Peptidoglycan
  • Polymyxins
  • Amikacin
  • Polymyxin B