TABLE 2

Effect of efflux pump gene inactivation on antibiotic MICsa

AgentMIC (μg/ml)
P. aeruginosa PAO1 E. coli K-12
Wild typemexA::tetWild typeΔacrAB
Norfloxacin>810.0040.004
Ciprofloxacin20.10.010.0025
Levofloxacin0.25b 0.015b 0.063c 0.016c
Besifloxacin1d 0.06d 0.25d 0.015d
Moxifloxacin0.8e 0.05e
Tetracycline8–160.5f 1.250.156
Tigecycline8g 0.25g 0.5h 0.125h
Chloramphenicol1646.250.78
Novobiocin128161001.56
Erythromycin512i 64i 501.56
Azithromycin1006.258j 0.5j
Benzylpenicillin>1,02451216k 8k
Cloxacillin5,120l 2.56l 256k 2k
Ampicillin 12.53.12
Carbenicillin320.254k 1k
Azlocillin40.516k 4k
Piperacillin3m 0.4m 4c 0.25c
Cefoperazone40.50.03k 0.015k
Ceftriaxone6480.0015k 0.0015k
Cefepime210.0075k 0.0075k
Cefpirome420.015k 0.015k
Imipenem21–20.12k 0.12k
  • a The MIC data for P. aeruginosa are from reference 13, and those for E. coli are from reference 27, unless otherwise indicated.

  • b Data from reference 411, where a mexAB-oprM mutant was used.

  • c Data from reference 95.

  • d Data from reference 1009, where an oprM mutant was used for P. aeruginosa.

  • e Data from reference 392.

  • f Because the mutant strain contains the tet marker, the value for an oprM mutant is used (13).

  • g Data from reference 393.

  • h Data from reference 138.

  • i Data from reference 187.

  • j X.-Z. Li, unpublished data.

  • k Data from reference 188.

  • l Data from reference 390, where a mexAB-oprM mutant was used.

  • m Data from reference 391, where an oprM mutant was used.