TABLE 1.

Bacterial strains and plasmids used in the present study

Strain or plasmidFeatures (resistance markera)Source or reference
Strains
    EcDC64Multiresistant E. cloacae clinical strain isolated from a patient admitted to our hospitalThis study
    EcΔacrAEcDC64 with acrA gene knockoutThis study
    EcΔacrA(pAP-2)EcΔAcrA transformed with pAP-2This study
    EcΔacrA(pACYC184)EcΔAcrA transformed with pACYC184This study
    EcDC64(pAP-3)EcDC64 transformed with pAP-3This study
    EcDC64(pBGS18)EcDC64 transformed with pBGS18This study
    E. cloacae Jc 194Carbapenem-susceptible strain used as reference strain in RT-PCR experimentsThis study
Plasmids
    pBGS18Cloning vector (kanamycin)26
    pACYC184Cloning vector (chloramphenicol and tetracycline)3, 22
    pKOBEGCloning vector (chloramphenicol)4
    pAP-1 (pBGS18-ampD)ampD gene from E. coli cloned into pBGS18 (kanamycin)This study
    pAP-2 (pACYC184-acrA)acrA gene from EcDC64 isolate cloned into pACYC184 (chloramphenicol)This study
    pAP-3 (pBGS18-acrR)acrR gene from E. aerogenes cloned into pBGS18 (kanamycin)This study
  • a Resistance markers for plasmids are shown in parentheses.