Fig. 1: Checkerboard analysis of the synergistic antimicrobial effect of colistin and Ob on both colistin-resistant and colistin-susceptible E. coli.

a Colistin-susceptible E. coli J53. b Colistin-resistant E. coli J53 carrying a mcr-1-bearing plasmid which was originally recovered from a clinical E. coli strain. CT, colistin.