Mdt(A), a new efflux protein conferring multiple antibiotic resistance in Lactococcus lactis and Escherichia coli.
The mdt(A) gene, previously designated mef214, from Lactococcus lactis subsp. lactis plasmid pK214 encodes a protein [Mdt(A) (multiple drug transporter)] with 12 putative transmembrane segments (TMS) that contain typical motifs conserved among the efflux proteins of the major facilitator superfamily. However, it also has two C-motifs (conserved in the fifth TMS of the antiporters) and a putative ATP-binding site. Expression of the cloned mdt(A) gene decreased susceptibility to macrolides, lincosamides, streptogramins, and tetracyclines in L. lactis and Escherichia coli, but not in Enterococcus faecalis or in Staphylococcus aureus. Glucose-dependent efflux of erythromycin and tetracycline was demonstrated in L. lactis and in E. coli.
Center for Adaptation Genetics and Drug Resistance, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
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Perreten
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Schwarz
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Teuber
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Levy
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology*; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004917:Erythromycin / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D007700:Kinetics; D013294:Lactococcus lactis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D010641:Phenotype; D013752:Tetracycline / Q000378:metabolism
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C434281:Mdt-A protein, E coli; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D004917:Erythromycin; D013752:Tetracycline