Table 2 Colistin MICs and gene expression levels in different E. coli TSAREC02 mutants

MG1655

WT

WT

None

1

1

1

1

1

0.5

TSAREC02

c127t (premature termination)

g616a, t618g, t664c

(G206R, Y222H.)

None

1.92 ± 0.68

0.77 ± 0.17

0.11 ± 0.03

5.26 ± 2.65

63.04 ± 39.34

16

TSAREC02_ΔmgrB^Δ43–47

Deleted

g616a, t618g, t664c

(G206R, Y222H.)

None

ND

ND

ND

ND

ND

16

TSAREC02 WT-mgrB revertant

WT^b

g616a, t618g, t664c

(G206R, Y222H.)

None

0.88 ± 0.43

0.32 ± 0.09

0.35 ± 0.28

4.48 ± 2.47

53,65 ± 46.35

16

TSAREC02 _ΔpmrB^{g616a, t618g, t664c}

c127t (premature termination)

Deleted

None

ND

ND

0.01 ± 0.001

< 0.01

3.08 ± 0.88

0.5

TSAREC02 _ΔpmrB^{g616a, t618g, t664c}

(pCRII-TOPOpmrB^{g616a, t618g, t664c})

c127t (premature termination)

Deleted

g616a, t618g, t664c (G206R, Y222H.)

ND

ND

0.12 ± 0.03

18.54 ± 4.22

83.41 ± 22.63

16