TABLE 1.

MICs of antimicrobial agents and dyes for the strains

E. coli strain/plasmidEfflux pump inhibitorbMIC (μg/ml)a
NORCIPPFXGATLVXMXFNALEBR
C600Rif00.0640.0230.0940.0230.0320.0642128
+NMP0.0470.0160.0640.0160.0160.0321.564
+PAβN0.0320.0120.0470.0160.0120.0321.5128
C600Rif/pIP120601.50.250.0940.0320.0320.0942128
+NMP0.0640.0160.0640.0160.0160.0321.564
+PAβN0.0470.0080.0320.0120.0120.0061.564
TOP1000.0320.0030.0230.0030.0060.0041.5128
+NMP0.0160.0020.0160.0020.0020.002164
+PAβN0.0160.0020.0160.0020.0020.002164
TOP10/pIP120600.380.0230.0230.0030.0060.0061.5128
+NMP0.0160.0030.0160.0020.0020.002164
+PAβN0.0160.0020.0160.0020.0020.002164
TOP10/pAT85100.190.0160.0230.0030.0080.0041.5128
+NMP0.0160.0020.0160.0020.0020.002164
+PAβN0.0160.0020.0160.0020.0020.0021128
  • a CIP, ciprofloxacin; EBR, ethidium bromide; GAT, gatifloxacin; LVX, levofloxacin; MXF, moxifloxacin; NAL, nalidixic acid; NOR, norfloxacin; PFX, pefloxacin. MICs of fluoroquinolones and EBR were determined by E-test and agar dilution, respectively.

  • b NMP used at 40 μg/ml; PAβN used at 50 μg/ml.