TABLE 1.

Bacterial strains used in this study

Plasmid or strainDescriptionReference
Plasmids
    pUC18us-penA35Plasmid containing the penA35 gene from strain 35/027
    pPR16Plasmid containing the wild-type ponA gene and a downstream Ω resistance cassette conferring spectinomycin and streptomycin resistance28
    pPR17pPR16 with the ponA gene replaced by the ponA1 gene harboring an L421P mutation28
    pMO-porBFA1090-ermPlasmid containing the porB1b gene from FA1090 (i.e., wild-type porB1b) with a downstream erm cassette conferring erythromycin resistance23
    pBS-mtrD::KanPlasmid containing the mtrD gene insertionally inactivated with a Kan resistance cassette15
Strains
    FA19Clinical isolate20
    FA6140Clinical isolate8
    35/02Clinical isolate19
    FA19 penA35FA19 transformed with pUC18us-penA35This study
    FA6140 penA35FA6140 transformed with pUC18us-penA35This study
    FA19 penA35 mtrRFA19 penA35 transformed with mtrR35/02 PCR productThis study
    FA19 penA35 mtrR penB35FA19 penA35 mtrR transformed with porB1b35/02 PCR productThis study
    FA19 penA35 mtrR penB35 ponA1FA19 penA35 mtrR penB35 transformed with pPR17This study
    FA6140 mtrD::KanFA6140 transformed with pBS-mtrD::KanThis study
    FA6140 penA35 mtrD::KanFA6140 penA35 transformed with pBS-mtrD::KanThis study
    35/02 mtrD::Kan35/02 transformed with pBS-mtrD::KanThis study
    FA6140 penA35 porB1bFA1090FA6140 penA35 transformed with pMO-porB1bFA1090This study
    FA6140 penA35 ponAwild typeFA6140 penA35 transformed with pPR16This study
    35/02 ponAwild type35/02 transformed with pPR16This study