TABLE 5

MICs of E. coli AG100AΩ (ΔacrAB ΔlacY) and FHU-100 (ΔacrAB ΔtolC) expressing plasmid-borne efflux genes

AntibioticMIC (μg/ml) for the following host strain in which the indincated efflux system genes were expressed:
AG100AΩ (ΔacrAB ΔlacY)aFHU-100 (ΔacrAB ΔtolC)b
NoneadeABadeABCadeABKadeIJadeIJKNoneadeABadeABCadeIJadeIJK
Ampicillin24442448844
Cloxacillin24160502400111001512
Oxacillin12160100140011501256
Cephaloridine24882844444
Cephalothin22884888888
Cefepime0.030.030.500.500.030.060.030.030.120.030.03
Nitrocefin246464225022324256
Erythromycin2080640640404010103201020
Novobiocin8832161010022162128
Tetracycline4420010044223222
Minocycline12502548221624
Ciprofloxacin0.030.050.500.250.020.050.020.020.160.020.04
Norfloxacin0.250.252.501.250.20.40.10.10.40.10.4
  • a The MICs for AG100AΩ (ΔacrAB ΔlacY) were determined using a standard 2-fold broth microdilution method with LB broth containing 5 mM MgCl2 and 10 μM IPTG for the adeAB, adeABC, and adeABK genes and 5 μM IPTG for the adeIJ and adeIJK genes. The genes were cloned in the vector pKY9790.

  • b The MICs for FHU-100 (ΔacrAB ΔtolC) were determined under the same conditions described in footnote a for AG100AΩ (ΔacrAB ΔlacY), but without IPTG.