Table 1 Minimum Inhibitory Concentrations (MICs) of polymyxin B and rifampicin potentiation against wild-type and polymyxin-resistant strains

From: Potent activity of polymyxin B is associated with long-lived super-stoichiometric accumulation mediated by weak-affinity binding to lipid A

  

MIC (µM)a

Species

Background

Polymyxin B

PMBNb

Brevicidine

E. coli

WT

0.00008

>40

0.313

PmrAG53E

10

>40

0.625

mcr1c

2.5–5

>40

0.313

WT+rifampicind

<0.00002

0.078

0.078

PmrAG53E+rifampicind

0.001

20

0.078

mcr-1+rifampicind

0.001

2.5

0.078

S. aureus

WT

>40

>40

>40

  1. aMinimal Inhibitory Concentrations (MICs): lowest concentration of antibiotic that completely inhibits bacterial growth.
  2. bPMBN, polymyxin B nonapeptide.
  3. cStrain carrying a plasmid encoding the mcr-1 gene.
  4. dRifampicin present at 1.56 µM, which has no effect on growth of E. coli or polymyxin-resistant E. coli strains tested.
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