TABLE 2.

Drug resistance of E. coli KAM3 (ΔacrAB) and KO6494 [ΔacrAB mdtB::Apr (Mu d1)] cells harboring a pUC119 or pHSG398 plasmid carrying an ORF cluster(s) in the genomic yeg, mdt, and bae regiona

DrugMIC (μg/ml) against KAM3 harboring multicopy plasmid pUC119 carrying:MIC (μg/ml) against KO6494b harboring pHSG398 carrying:
Noneyeg/mdt/baecyegLKmdtAmdtABmdtABCmdtABCDbaeSRbaeSbaeRNonebaeSR
Deoxycholate1,00064,0001,0001,0001,00064,00064,00064,0001,000>64,0001,0001,000
Cholate8,00064,0008,0008,0008,00064,00064,00064,0008,00064,0008,0008,000
Taurocholate16,000>64,00016,00016,00016,000>64,000>64,000>64,00016,00064,00016,00016,000
SDS64256646464128256256642566464
Novobiocin181118881811
  • a MICs more than fourfold higher than those against host KAM3 cells are indicated by boldface. MICs of 17 different drugs and toxic compounds other than those listed here (tetracycline, chloramphenicol, minocycline, erythromycin, enoxacin, kanamycin, vancomycin, doxorubicin, rifampin, trimethoprim, acriflavine, crystal violet, ethidium bromide, rhodamine 6G, methylviologen, tetraphenylphosphonium bromide, and carbonyl cyanide m-chlorophenylhydrazone) were measured. However, no change in MIC was observed when the cells were transformed with any plasmid carrying ORFs listed above.

  • b KO6494 is a Mu d1 phage-integrated mdtB-disrupted derivative of KAM3.

  • c yeg/mdt/bae contains yegKL, mdtABCD (yegMNOB), and baeSR genes as shown in Fig. 1.