TABLE 1

Bacterial strains and plasmids

Strain or plasmid(s)DescriptionReference or source
Strains
    Ec1003A clinical carbapenem-susceptible E. coli isolate (imipenem MIC, 0.125 μg/ml). This isolate was used to demonstrate the sheltering effect of carbapenem-resistant A. baumannii.3
    Ab290A clinical A. baumannii isolate susceptible to multiple antimicrobials, which was used as the recipient for multiple transformations.3
Plasmids
    pEGFPA commercial plasmid containing enhanced green fluorescent protein.Clontech Laboratories, Inc.
    pYMAb-2A shuttle vector created by inserting a replicon of a plasmid from A. baumannii ATCC 19606T into pET-28a; Kanra3
    pYMAb-3A shuttle vector created by inserting a replicon of pMAC from A. baumannii ATCC 19606T into pET-28a; Kanr8
    pOXA-58-2IS1008-ΔISAba3-blaOXA-58 with its P2 and P1 promoters was amplified using primers IS1008(XbaI)F and OXA-58(XhoI)R and cloned into the XbaI and XhoI sites of pYMAb-2.3
    pOXA-58-3IS1008-ΔISAba3-blaOXA-58 was amplified using primers XbaIIS1008 and NcoIOXA58 and cloned into the XbaI and NcoI sites of pYMAb-3.8
    pOXA-23blaOXA-23 and its promoter in ISAba1 were amplified using primers ISAba1(XbaI)F and OXA23-like(XhoI)R and cloned into the XbaI and XhoI sites of pYMAb-2. OXA-23 was His tagged.3
    pOXA-72blaOXA-72 and its promoter were amplified using primers OXA-24-like(XbaI)F and OXA-24-like(XhoI)R and cloned into the XbaI and XhoI sites of pYMAb-2. OXA-72 was His-tagged.3
    pOXA-83blaOXA-83 and its promoter in ISAba1 were amplified using primers ISAba1(XbaI)F and OXA-51-like(XhoI)R and cloned into the XbaI and XhoI sites of pYMAb-2. OXA-83 was His tagged.3
    pOXA-58ΔSPPromoters P2 and P1 of IS1008-ΔISAba3-blaOXA-58 were amplified using primers IS1008(XbaI)F and IS1008(M-BamHI)R. blaOXA-58 minus the signal peptide was amplified using primers OXA-58Δ20aaSP(BamHI)F and OXA-58(XhoI)R. These two fragments were BamHI ligated and cloned into the XbaI and XhoI sites of pYMAb-2.bThis study
    pOXA-58ΔP2-1, pOXA-58ΔP2-2, and pOXA-58ΔP2-3IS1008-ΔISAba3-blaOXA-58 with deletions in P2 was amplified using primer IS1008-ΔP2-1(XbaI)F, IS1008-ΔP2-2(XbaI)F, or IS1008-ΔP2-3(XbaI)F and primer OXA-58(XhoI)R and cloned into the XbaI and XhoI sites of pYMAb-2.3
    pOXA-58Δ5AA-CT, pOXA-58Δ10AA-CT, and pOXA-58Δ15AA-CTIS1008-ΔISAba3-blaOXA-58 with a deletion of 5, 10, or 15 amino acids at C terminus of OXA-58 was amplified using primers IS1008(XbaI)F and OXA-58-CΔ5aa(XhoI)R, OXA-58-CΔ10aa(XhoI)R, or OXA-58-CΔ15aa(XhoI)R and cloned into the XbaI and XhoI site of pYMAb-2.This study
    pEGFP-2The P2 and P1 promoter of IS1008-ΔISAba3-blaOXA-58 was amplified using primers IS1008(BamHI)F and IS1008(NcoI)R and cloned into the BamHI and NcoI sites of pEGFP. The promoter-EGFP fragment was cloned into the XbaI and BamHI sites of pYMAb-2.This study
    pOXA-58SP-EGFPThe P2 and P1 promoter and signal peptide of IS1008-ΔISAba3-blaOXA-58 was amplified using primers IS1008(BamHI)F and OXA-58-20aaSP(NcoI)R and cloned into the BamHI and NcoI sites of pEGFP. The promoter-signal peptide-EGFP fragment was cloned into the XbaI and BamHI sites of pYMAb-2.This study