title: Cloning and characterization of a novel macrolide efflux gene, mreA, from Streptococcus agalactiae.
abstract: A strain of Streptococcus agalactiae displayed resistance to 14-, 15-, and 16-membered macrolides. In PCR assays, total genomic DNA from this strain contained neither erm nor mef genes. EcoRI-digested genomic DNA from this strain was cloned into lambda Zap II to construct a library of S. agalactiae genomic DNA. A clone, pAES63, expressing resistance to erythromycin, azithromycin, and spiramycin in Escherichia coli was recovered. Deletion derivatives of pAES63 which defined a functional region on this clone that encoded resistance to 14- and 15-membered, but not 16-membered, macrolides were produced. Studies that determined the levels of incorporation of radiolabelled erythromycin into E. coli were consistent with the presence of a macrolide efflux determinant. This putative efflux determinant was distinct from the recently described Mef pump in Streptococcus pyogenes and Streptococcus pneumoniae and from the multicomponent MsrA pump in Staphylococcus aureus and coagulase-negative staphylococci. Its gene has been designated mreA (for macrolide resistance efflux).
authors.affiliation: Central Research Division, Pfizer, Inc., Groton, Connecticut 06340, USA.
authors.forename: J
authors.initials: J
authors.lastname: Clancy
authors.forename: F
authors.initials: F
authors.lastname: Dib-Hajj
authors.forename: J W
authors.initials: JW
authors.lastname: Petitpas
authors.forename: W
authors.initials: W
authors.lastname: Yuan
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D001483:Base Sequence; D002250:Carbon Radioisotopes; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial / Q000235:genetics; D004917:Erythromycin / Q000493:pharmacokinetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010641:Phenotype; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002250:Carbon Radioisotopes; D004917:Erythromycin