title: Many chromosomal genes modulate MarA-mediated multidrug resistance in Escherichia coli.
abstract: Multidrug resistance (MDR) in clinical isolates of Escherichia coli can be associated with overexpression of marA, a transcription factor that upregulates multidrug efflux and downregulates membrane permeability. Using random transposome mutagenesis, we found that many chromosomal genes and environmental stimuli affected MarA-mediated antibiotic resistance. Seven genes affected resistance mediated by MarA in an antibiotic-specific way; these were mostly genes encoding unrelated enzymes, transporters, and unknown proteins. Other genes affected MarA-mediated resistance to all antibiotics tested. These genes were acrA, acrB, and tolC (which encode the major MarA-regulated multidrug efflux pump AcrAB-TolC), crp, cyaA, hns, and pcnB (four genes involved in global regulation of gene expression), and the unknown gene damX. The last five genes affected MarA-mediated MDR by altering marA expression or MarA function specifically on acrA. These findings demonstrate that MarA-mediated MDR is regulated at multiple levels by different genes and stimuli, which makes it both complex and fine-tuned and interconnects it with global cell regulation and metabolism. Such a regulation could contribute to the adaptation and spread of MDR strains and may be targeted to treat antibiotic-resistant E. coli and related pathogens.
authors.affiliation: Center for Adaptation Genetics and Drug Resistance, Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.
authors.forename: Cristian
authors.initials: C
authors.lastname: Ruiz
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Levy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D002876:Chromosomes, Bacterial / Q000235:genetics; D003087:Colicins / Q000235:genetics / Q000378:metabolism; D002373:Cyclic AMP Receptor Protein / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D003087:Colicins; D002373:Cyclic AMP Receptor Protein; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D011062:Polynucleotide Adenylyltransferase; C083497:AcrA protein, E coli; C083496:AcrB protein, E coli; C545719:DamX protein, E coli; C529458:FimG protein, E coli; C080002:MarA protein, E coli; C533451:colicin Y protein, E coli; C481662:crp protein, E coli; C073126:tolC protein, E coli; C063643:pcnB protein, E coli