Table 2.

Drug resistance of E. coli cells harboring plasmids carrying putative drug transporter ORFsa

CompoundMIC (μg/ml) without plasmidMIC (μg/ml) with plasmid carrying ORF for transporter of type:
MFMATE (pUCydhE)RNDSMRABC (pUCybjYZ)
pUCfsrbpUCmdfApUCyceEpUCbcrcpUCemrABpUCemrDpUCynfMpUCyebQpUCacrABpUCyegMNOBdpUCacrDpUCacrEFpUCyhiUVpUCemrEpUCydgFE
Chloramphenicol0.390.39 6.25 0.390.390.390.390.390.39 0.78 3.13 0.390.390.390.390.390.390.39
Tetracycline0.390.39 0.78 0.39 1.56 0.390.390.390.390.39 3.13 0.390.390.390.390.390.390.39
Minocycline0.200.200.200.200.200.200.200.200.200.20 3.13 0.200.200.200.200.200.200.20
Erythromycin3.133.133.133.133.133.133.133.133.133.13 100 3.133.133.13 25 3.133.13 25
Nalidixic acid0.780.780.780.780.780.780.780.780.780.78 3.13 1.56 0.780.780.780.780.780.78
Norfloxacin0.0250.025 0.20 0.0250.0250.0250.0250.0250.025 0.20 0.20 0.05 0.0250.0250.0250.0250.0250.025
Enoxacin0.050.050.050.050.050.050.050.050.05 0.39 0.39 0.050.050.050.050.050.050.05
Kanamycin6.256.256.256.25 12.5 6.256.256.256.256.256.256.25 12.5 6.256.256.256.256.25
Vancomycin200200200200200200200200200200200200200200200200200200
Fosfomycin1.561.561.56 6.25 6.25 1.561.561.561.56 3.13 1.56 3.13 1.561.561.561.561.561.56
Doxorubicin3.133.13 12.5 3.133.133.133.133.133.13 25 >200 3.133.13 6.25 25 3.133.133.13
Novobiocin1.561.561.561.561.561.561.561.561.561.56 100 25 6.25 1.561.561.561.561.56
Rifampin6.256.256.256.256.256.256.256.256.256.25 12.5 6.256.256.256.256.256.256.25
Trimethoprim3.13 6.25 12.5 3.133.133.133.133.13 0.78 12.5 >100 3.133.133.133.133.133.133.13
Acriflavine12.512.5 100 12.5 25 12.512.5 3.13 12.512.5 >200 12.512.5 100 12.5 200 12.512.5
Crystal violet1.561.561.561.561.561.561.561.561.561.56 12.5 1.561.561.56 3.13 3.13 1.561.56
Ethidium bromide12.512.5 50 12.512.512.512.512.512.5 25 >400 12.512.5 50 50 100 12.512.5
Rhodamine 6G6.256.256.256.256.25 12.5 6.256.256.256.25 400 6.256.25 25 100 6.256.256.25
Methylviologen100100100100100 200 100100100100100100100100100 200 100100
TPP6.256.25 25 6.256.256.256.256.256.25 200 400 6.256.256.25 25 6.256.256.25
CCCP6.25 12.5 6.256.256.25 50 6.256.256.256.256.256.256.256.256.256.256.256.25
Benzalkonium3.133.133.133.133.133.13 6.25 3.133.13 6.25 100 6.25 3.133.13 6.25 6.25 3.133.13
SDS5050505050 100 100 505050 >400 200 >400 100 200 50 100 50
Deoxycholate1,2501,2501,2501,2501,250 40,000 1,2501,2501,250 40,000 >40,000 >40,000 >40,000 5,000 5,000 1,250 5,000 1,250
  • a Values in bold differ significantly from the KAM3 control strain value. MICs were measured without IPTG, so that the ORFs were expected to be expressed under the control of the endogenous promoters. Data are not shown for pUCemrKY, which carriesemrK/Y and evgS/A genes. This plasmid conferred resistance to doxorubicin (MIC, 100 μg/ml), rhodamine 6G (100 μg/ml), benzalkonium (25 μg/ml), erythromycin (12.5 μg/ml), crystal violet (6.25 μg/ml), TPP (25 μg/ml), deoxycholate (5,000 μg/ml), fosfomycin (3.13 μg/ml), novobiocin (3.13 μg/ml), acriflavine (25 μg/ml), ethidium bromide (25 μg/ml), methylviologen (200 μg/ml), and SDS (100 μg/ml). Multidrug resistance conferred by pUCemrKY is due to overexpression of evgA,emrK/Y genes confer deoxycholate resistance (33). pUCyajR, pUCyceL, pUCydeA, pUCydeF, pUCydhC, pUCydiM, pUCyidY, pUCyieO, pUCyjiO, pUCcusA, pUCsugE, pUCmdlAB, pUCyddA, pUCyojIH, and pUCyhiH did not alter MIC values.

  • b pUCfsr conferred fosmidomycin resistance (MIC, 0.39 μg/ml for KAM3 versus 12.5 μg/ml for KAM3/pUCfsr).

  • c pUCbcr conferred bicyclomycin resistance (MIC, 25 μg/ml for KAM3 versus 400 μg/ml for KAM3/pUCbcr).

  • d pUCyegMNOB carries both RND- (yegM/N/O) and MF-type (yegB) ORFs. Resistance conferred by pUCyegMNOB is due to overexpression of RND genes (unpublished data).