Table 2.

Relative MIC values of mutant strains of E. coli and S. enterica

Gene	Mutation	Antibiotic	E. coli relative MIC	S. enterica relative MIC
mprA	Arg110Leu	NIT	1.20	1.73
marR	Val84Glu	AMP	2.20	1.15
soxR	Leu139*	ERY	2.31	1.73
phoQ	Gly384Cys	NIT	1.20	0.83
trkH	Thr350Lys	STR	3.18	1.59
gyrA	Ser83Leu	CPR	16.00	16.00
gyrA	Ser83Leu	NAL	97.66	610.35
fis	Thr70Pro	ERY	1.44	1.44
acrR	Gln78*	ERY	1.20	1.00
ompC	Met1	NIT	1.20	1.20
ycbZ	Ser438Arg	ERY	1.23	1.51

The sensitivity of each mutant strain was measured against the antibiotic against which the specific mutation formed during laboratory adaptation (30). The measured MIC for each strain was then compared with the MIC of the wild-type strain, resulting in the relative MIC value. The antibiotic abbreviations are as follows: AMP, ampicillin; CPR, ciprofloxacin; ERY, erythromycin; NAL, nalidixic acid; NIT, nitrofurantoin; STR, streptomycin.