Escherichia coli AcrAB-TolC with MarR mutations conferring resistance to ciprofloxacin and tetracycline

Accession ARO:3003378
CARD Short NameEcol_MarR_MULT
DefinitionMarR is a repressor of the mar operon marRAB, thus regulating the expression of marA, the activator of multidrug efflux pump AcrAB.
AMR Gene Familyresistance-nodulation-cell division (RND) antibiotic efflux pump
Drug Classtetracycline antibiotic, disinfecting agents and antiseptics, phenicol antibiotic, cephalosporin, penam, rifamycin antibiotic, glycylcycline, fluoroquinolone antibiotic
Resistance Mechanismantibiotic efflux, antibiotic target alteration
Efflux Componentefflux pump complex or subunit conferring antibiotic resistance
Efflux Regulatorprotein(s) and two-component regulatory system modulating antibiotic efflux
Resistomes with Sequence VariantsCitrobacter amalonaticusg+wgs, Citrobacter freundiig+wgs, Citrobacter koserig+wgs, Citrobacter portucalensisg+wgs, Citrobacter werkmaniig+wgs, Citrobacter youngaeg+wgs, Cronobacter sakazakiig+wgs, Enterobacter asburiaeg+wgs, Enterobacter chengduensisg+wgs, Enterobacter cloacaeg+wgs, Enterobacter hormaecheig+wgs, Enterobacter kobeig+wgs, Enterobacter roggenkampiig+wgs, Enterococcus faeciumwgs, Escherichia albertiig+wgs, Escherichia colig+p+wgs, Escherichia fergusoniig+wgs, Escherichia marmotaeg+wgs, Klebsiella aerogenesg+wgs, Klebsiella huaxiensisg+wgs, Klebsiella michiganensisg+wgs, Klebsiella oxytocag+wgs, Klebsiella pneumoniaeg+p+wgs, Klebsiella quasipneumoniaeg+wgs, Kosakonia arachidisg+wgs, Leclercia adecarboxylatag+wgs, Pseudomonas aeruginosawgs, Raoultella planticolag+wgs, Salmonella entericag+wgs, Shigella boydiig+wgs, Shigella dysenteriaeg+wgs, Shigella flexnerig+wgs, Shigella sonneig+wgs
Classification30 ontology terms | Show
Parent Term(s)1 ontology terms | Show
+ marR

Alekshun MN and Levy SB. 1997. Antimicrob Agents Chemother 41(10): 2067-2075. Regulation of chromosomally mediated multiple antibiotic resistance: the mar regulon. (PMID 9333027)

Randall LP and Woodward MJ. 2002. Res Vet Sci 72(2): 87-93. The multiple antibiotic resistance (mar) locus and its significance. (PMID 12027588)

Oethinger M, et al. 1998. Antimicrob. Agents Chemother. 42(8):2089-94 Overexpression of the marA or soxS regulatory gene in clinical topoisomerase mutants of Escherichia coli. (PMID 9687412)

Maneewannakul K, et al. 1996. Antimicrob. Agents Chemother. 40(7):1695-8 Identification for mar mutants among quinolone-resistant clinical isolates of Escherichia coli. (PMID 8807064)

Okusu H, et al. 1996. J Bacteriol 178(1): 306-308. AcrAB efflux pump plays a major role in the antibiotic resistance phenotype of Escherichia coli multiple-antibiotic-resistance (Mar) mutants. (PMID 8550435)


Prevalence of Escherichia coli AcrAB-TolC with MarR mutations conferring resistance to ciprofloxacin and tetracycline among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI or IslandViewer for 263 important pathogens (see methodological details and complete list of analyzed pathogens). Values reflect percentage of genomes, plasmids, genome islands, or whole-genome shotgun assemblies that have at least one hit to the AMR detection model. Default view includes percentages calculated based on Perfect plus Strict RGI hits. Select the checkbox to view percentages based on only Perfect matches to AMR reference sequences curated in CARD (note: this excludes resistance via mutation as references in protein variant models are often wild-type, sensitive sequences).

Prevalence: protein overexpression model (view sequences)

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GI
Citrobacter amalonaticus100%0%87.5%0%
Citrobacter freundii100%0%60.76%0%
Citrobacter koseri100%0%46.67%0%
Citrobacter portucalensis100%0%86%0%
Citrobacter werkmanii100%0%100%0%
Citrobacter youngae100%0%100%0%
Cronobacter sakazakii100%0%92.88%0%
Enterobacter asburiae100%0%88.19%0%
Enterobacter chengduensis100%0%90.91%0%
Enterobacter cloacae97.73%0%81.82%0%
Enterobacter hormaechei98.81%0%80.53%0%
Enterobacter kobei91.67%0%86.89%0%
Enterobacter roggenkampii100%0%73.94%0%
Enterococcus faecium0%0%0.04%0%
Escherichia albertii95%0%94.25%0%
Escherichia coli61.38%0.07%74.4%0%
Escherichia fergusonii100%0%44.62%0%
Escherichia marmotae100%0%69.05%0%
Klebsiella aerogenes100%0%81.45%0%
Klebsiella huaxiensis100%0%50%0%
Klebsiella michiganensis97.67%0%75.65%0%
Klebsiella oxytoca100%0%81.11%0%
Klebsiella pneumoniae98.97%0.02%71.71%0%
Klebsiella quasipneumoniae100%0%81.18%0%
Kosakonia arachidis100%0%100%0%
Leclercia adecarboxylata100%0%90.48%0%
Pseudomonas aeruginosa0%0%0.02%0%
Raoultella planticola100%0%94.12%0%
Salmonella enterica94.37%0%88.71%0%
Shigella boydii92.86%0%91.4%0%
Shigella dysenteriae90.91%0%89.29%0%
Shigella flexneri100%0%83.33%0%
Shigella sonnei100%0%94.37%0%
Show Perfect Only

Prevalence: efflux pump system meta-model

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GI
No prevalence data

Detection Models

Model Type: protein overexpression model

Model Definition: This model detects protein overexpression based on the presence of mutations. The detection of the protein without an associated mutation indicates that the protein is likely to be expressed at low or basal levels. The detection of the protein with the mutation indicates that the protein is likely overexpressed. This model reflects how certain proteins are functional with and without mutations. For example, efflux pump subunits and regulators are functional with mutations and without mutations. Without mutations, efflux pump subunits and regulators are usually expressed at a low level. When an efflux pump regulator has a mutation, it can cause the overexpression of the efflux pump it is responsible for regulating, leading to resistance to specific drugs. Protein overexpression models have two parameters: a curated BLASTP cutoff, and a curated set of mutations (single resistance variants, frameshift mutations, indels, etc.) shown clinically to confer resistance. This model type is a combination of the protein homolog and protein variant model. A detected hit can be categorized as Perfect, Strict, or Loose with no mutation(s) or as Strict or Loose with mutation(s).

Bit-score Cut-off (blastP): 210


  • discovered in clinical, agricultural, or environmental isolates

  • discovered via laboratory selection experiments

  • ReSeqTB

Published Variants:

PMID in progress (single): V45E A70T R73S R73C R77L R77C Y137H

PMID: 9687412E31STOP I49S L78M R94H R94S
PMID: 8807064S3N V96E G103S
PMID: 8550435R58L

>gb|AAC74603.2|+|Escherichia coli marR mutant conferring antibiotic resistance [Escherichia coli str. K-12 substr. MG1655]

>gb|U00096.1|+|1619120-1619554|Escherichia coli marR mutant conferring antibiotic resistance [Escherichia coli str. K-12 substr. MG1655]

Model Name: Escherichia coli AcrAB-TolC with MarR mutations conferring resistance to ciprofloxacin and tetracycline

Model Description: The Escherichia coli AcrAB-TolC with MarR mutation (Y137H) conferring resistance to ciprofloxacin and tetracycline.

Escherichia coli marR mutant conferring antibiotic resistanceTolCacrBEscherichia coli acrA