title: Decreased susceptibility to azithromycin and erythromycin mediated by a novel mtr(R) promoter mutation in Neisseria gonorrhoeae.
abstract: During a screen of Neisseria gonorrhoeae clinical isolates obtained in Uruguay for susceptibility to azithromycin, we noticed that approximately 10% of the strains examined displayed decreased susceptibility to azithromycin and erythromycin due to the mtr(CDE)-encoded efflux pump system, but remained susceptible to Triton X-100. We now report that the mtr(R) promoter region of one of these isolates contains a dinucleotide insertion (TT) that mediates this resistance phenotype.
authors.affiliation: National Center for Gonococcal Antimicrobial Susceptibility Surveillance, Department of Microbiology, School of Chemistry, Avda Gral Flores 2124, Montevideo 11800, Uruguay. lzaranto@bilbo.edu.uy
authors.forename: L
authors.initials: L
authors.lastname: Zarantonelli
authors.forename: G
authors.initials: G
authors.lastname: Borthagaray
authors.forename: E H
authors.initials: EH
authors.lastname: Lee
authors.forename: W
authors.initials: W
authors.lastname: Veal
authors.forename: W M
authors.initials: WM
authors.lastname: Shafer
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D001426:Bacterial Proteins; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology; D005287:Ferredoxin-NADP Reductase; D015870:Gene Expression; D006801:Humans; D008297:Male; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012097:Repressor Proteins; C087450:mtrR protein, Neisseria gonorrhoeae; D004917:Erythromycin; D017963:Azithromycin; C111241:methionine synthase reductase; D005287:Ferredoxin-NADP Reductase