PMC8749148_01
PMC8749148_02
PMC8749148_03
MALDI mass spectrum of mcr-1-positive 

E. coli

 directly from urine. The m/z of 1797 is the known marker for 

E. coli

, while the m/z of 1920 ( m/z 123) represents the addition of a phosphoethanalomine (PEtN), signifying the presence of an mcr gene.
acmi-3-0309-g001.jpg
PMC8749148_03_acmi-3-0309-g001.jpg
F1
Spectra of lipid analysis by MS showed ion species at m/z 1797 and m/z 1920, which is consistent with   E. coli   and addition of a PEtN (Fig. 1).