Skip to main content

Table 1 Antibiogram of the OprD-deficient P. aeruginosa efflux mutant isogenic strain set showing MICs (μg/mL)a

From: In vitro studies evaluating the activity of imipenem in combination with relebactam against Pseudomonas aeruginosa

Antibacterial agent MB6476b MB6477c MIC differenced MB6477c ΔmexR (overexpresses MexAB) MB6477c ΔnfxB (overexpresses MexCD) MB6477c ΔmexL (overexpresses MexJK) MB6477c ΔmexZ (overexpresses MexXY)
Imipenem 16 16 1-fold 16 4 16 16
IMI/RELe 1 1 1-fold 1 0.25 1 1
Ceftazidimef 1 1 1-fold ND ND ND ND
Aztreonamg 0.5 4 8-fold ND ND ND ND
Meropenemf 1 1 to 2 1- to 2-fold 16 4 2 2
Chloramphenicolg 2 > 256 > 128-fold ND ND ND ND
Levofloxacing 0.0078 4 512-fold 8 4 4 4
  1. IMI/REL imipenem/relebactam, MIC minimum inhibitory concentration, ND not determined, OprD outer membrane porin D, RND resistance-nodulation-cell division
  2. aMIC values were determined by 2-fold serial broth microdilution
  3. bMB6476 nfxC, Δ [MexAB-OprM] Δ [MexCD-OprJ] Δ [MexXY] Δ [MexJK-OprLL] Δ [MexHI-OpmD] Δ [OpmH]), spontaneous OprD deletion
  4. cMB6477 nfxC, wild-type for other efflux pumps, spontaneous OprD deletion
  5. dRatio between the MIC for MB6477 divided by the MIC for MB6476, for the respective antibacterial agent
  6. eImipenem combined with 4 μg/mL of relebactam
  7. fControl antibacterial agent known to be an RND efflux pump substrate, with susceptibility known to be adversely affected by efflux pump overexpression [49, 50]
  8. gControl antibacterial agent known to be an RND efflux pump substrate, with susceptibility known to be adversely affected even in wild-type P. aeruginosa with baseline efflux pump expression [49, 50]