title: A combination of sbmA and tolC mutations in Escherichia coli K-12 Tn10-carrying strains results in hypersusceptibility to tetracycline.
abstract: Previously, we demonstrated that Escherichia coli tolC mutations reduce the high-level resistance to tetracycline afforded by the transposon Tn10-encoded TetA pump from resistance at 200 microg/ml to resistance at 40 microg/ml. In this study, we found that the addition of an sbmA mutation to a tolC::Tn10 mutant exacerbates this phenotype: the double mutant did not form colonies, even in the presence of tetracycline at a concentration as low as 5 microg/ml. Inactivation of sbmA alone partially inhibited high-level tetracycline resistance, from resistance at 200 microg/ml to resistance at 120 microg/ml. There thus appears to be an additive effect of the mutations, resulting in almost complete suppression of the phenotypic expression of Tn10 tetracycline resistance.
authors: Departamento de Bioquímica de la Nutrición, Instituto Superior de Investigaciones Biológicas, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Tucumán, 4000 San Miguel de Tucumán, Tucumán, Argentina.
authors: Ricardo E
authors: RE
authors: de Cristóbal
authors: Paula A
authors: PA
authors: Vincent
authors: Raúl A
authors: RA
authors: Salomón
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017920:Antiporters / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics / Q000502:physiology; D026901:Membrane Transport Proteins / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics*; D019895:Transposases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D017920:Antiporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C529573:SbmA protein, E coli; C473501:Tn10 transposase; C079051:tetA protein, Bacteria; C073126:tolC protein, E coli; D019895:Transposases; D013752:Tetracycline