Accession ARO:3000506
Synonym(s)nalB
CARD Short NameMexR
DefinitionMexR is the repressor of the MexRAB-OprM operon. Mutant forms of mexR result in up-regulation of efflux pump system MexAB-OprM.
AMR Gene Familyresistance-nodulation-cell division (RND) antibiotic efflux pump
Drug Classpeptide antibiotic, sulfonamide antibiotic, diaminopyrimidine antibiotic, penicillin beta-lactam, cephalosporin, phenicol antibiotic, aminocoumarin antibiotic, tetracycline antibiotic, carbapenem, monobactam, fluoroquinolone antibiotic, macrolide 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 VariantsPseudomonas aeruginosag+p+wgs, Pseudomonas fluorescensg
Classification47 ontology terms | Show
+ process or component of antibiotic biology or chemistry
+ antibiotic molecule
+ peptide antibiotic [Drug Class]
+ lipopeptide antibiotic
+ beta-lactam antibiotic
+ mechanism of antibiotic resistance
+ sulfonamide antibiotic [Drug Class]
+ diaminopyrimidine antibiotic [Drug Class]
+ penicillin beta-lactam [Drug Class]
+ determinant of antibiotic resistance
+ antibiotic efflux [Resistance Mechanism]
+ cephalosporin [Drug Class]
+ polymyxin antibiotic
+ penicillin with extended spectrum
+ third-generation cephalosporin
+ antibiotic mixture
+ phenicol antibiotic [Drug Class]
+ sulfamethoxazole [Antibiotic]
+ trimethoprim [Antibiotic]
+ efflux pump complex or subunit conferring antibiotic resistance [Efflux Component]
+ aminocoumarin antibiotic [Drug Class]
+ tetracycline antibiotic [Drug Class]
+ antibiotic target alteration [Resistance Mechanism]
+ colistin
+ carbapenem [Drug Class]
+ monobactam [Drug Class]
+ fluoroquinolone antibiotic [Drug Class]
+ macrolide antibiotic [Drug Class]
+ trimethoprim-sulfamethoxazole [Antibiotic]
+ panipenem [Antibiotic]
+ ampicillin [Antibiotic]
+ colistin B [Antibiotic]
+ colistin A [Antibiotic]
+ aztreonam [Antibiotic]
+ chloramphenicol [Antibiotic]
+ mutation conferring antibiotic resistance
+ azithromycin [Antibiotic]
+ novobiocin [Antibiotic]
+ resistance-nodulation-cell division (RND) antibiotic efflux pump [AMR Gene Family]
+ meropenem [Antibiotic]
+ ceftriaxone [Antibiotic]
+ ceftazidime [Antibiotic]
+ tetracycline [Antibiotic]
+ ciprofloxacin [Antibiotic]
+ erythromycin [Antibiotic]
+ MexAB-OprM
+ antibiotic resistant gene variant or mutant
Parent Term(s)5 ontology terms | Show
Publications

Wilke MS, et al. 2008. Proc Natl Acad Sci U S A 105(39): 14832-14837. The crystal structure of MexR from Pseudomonas aeruginosa in complex with its antirepressor ArmR. (PMID 18812515)

Chen H, et al. 2010. EMBO Rep 11(9): 685-690. Structural insight into the oxidation-sensing mechanism of the antibiotic resistance of regulator MexR. (PMID 20616806)

Saito K, et al. 2003. J Bacteriol 185(20): 6195-6198. Mutations affecting DNA-binding activity of the MexR repressor of mexR-mexA-mexB-oprM operon expression. (PMID 14526032)

Higgins PG, et al. 2003. Int. J. Antimicrob. Agents 21(5):409-13 Mutations in GyrA, ParC, MexR and NfxB in clinical isolates of Pseudomonas aeruginosa. (PMID 12727072)

Resistomes

Prevalence of MexR among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI or IslandViewer for 414 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 GIGRDI-AMR2
Pseudomonas aeruginosa96.93%0.58%96.48%0%0%
Pseudomonas fluorescens2.78%0%0%0%0%
Show Perfect Only

Prevalence: protein variant model

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GIGRDI-AMR2
No prevalence data


Detection Models

Model Type: protein overexpression model

Model Definition: Protein Overexpression Models (POM) are similar to Protein Variant Models (PVM) in that they include a protein reference sequence, a curated BLASTP bitscore cut-off, and mapped resistance variants. Whereas PVMs are designed to detect AMR acquired via mutation of house-keeping genes or antibiotic targets, reporting only those with curated mutations conferring AMR, POMs are restricted to regulatory proteins and report both wild-type sequences and/or sequences with mutations leading to overexpression of efflux complexes. The former lead to efflux of antibiotics at basal levels, while the latter can confer clinical resistance. POMs include a protein reference sequence (often from wild-type alleles), a curated bit-score cut-off, and mapped resistance variants. Mapped resistance variants may include any or all of single point mutations, insertions, or deletions curated from the scientific literature. A Perfect RGI match is 100% identical to the wild-type reference protein sequence along its entire length, a Strict RGI match has a BLASTP bit-score above the curated BLASTP cutoff value may or may not contain at least one curated mutation from amongst the mapped resistance variants, while a Loose RGI match has a bit-score less than the curated BLASTP bit-score cut-off may or may not contain at least one curated mutation from amongst the mapped resistance variants.

Bit-score Cut-off (blastP): 270

PubMed: mutation data hand curated from the scientific literature, evaluated as conferring resistance (R). CRyPTIC: mutation data acquired from the CRyPTIC catalog, evaluated as resistant (R), susceptible (S), or undetermined (U). ReSeqTB: mutation data acquired from the ReSeqTB catalog, evaluated as conferring resistance (Minimal, Moderate, High), not conferring resistance (None), or Indeterminate. WHO: mutation data acquired from the WHO 2023 catalog, evaluated as resistant (R), susceptible (S), or undetermined (U).

MutationMutation typePubMed
L45Psingle resistance variantPMID:14526032
I46Nsingle resistance variantPMID:14526032
N53Dsingle resistance variantPMID:12727072
L57Rsingle resistance variantPMID:14526032
L57Psingle resistance variantPMID:14526032
T69Isingle resistance variantPMID:14526032
I72Nsingle resistance variantPMID:14526032
L75Psingle resistance variantPMID:14526032
L75Rsingle resistance variantPMID:14526032
R83Csingle resistance variantPMID:14526032
R91Hsingle resistance variantPMID:14526032
R91Csingle resistance variantPMID:14526032
H107Psingle resistance variantPMID:14526032

>gb|AAG03813.1|-|mexR [Pseudomonas aeruginosa PAO1]
MNYPVNPDLMPALMAVFQHVRTRIQSELDCQRLDLTPPDVHVLKLIDEQRGLNLQDLGRQ
MCRDKALITRKIRELEGRNLVRRERNPSDQRSFQLFLTDEGLAIHQHAEAIMSRVHDELF
APLTPVEQATLVHLLDQCLAAQPLEDI



>gb|AE004091.2|-|471306-471749|mexR [Pseudomonas aeruginosa PAO1]
ATGAACTACCCCGTGAATCCCGACCTGATGCCCGCGCTGATGGCGGTCTTCCAGCATGTGCGGACGCGCATCCAGAGCGAGCTCGATTGC
CAGCGACTCGACCTGACCCCGCCCGACGTCCATGTATTGAAGCTTATCGACGAACAACGCGGGCTGAACCTGCAGGACCTGGGACGCCAG
ATGTGCCGCGACAAGGCACTGATCACCCGGAAGATCCGCGAGCTGGAGGGAAGAAACCTGGTCCGCCGCGAGCGCAACCCCAGCGACCAG
CGCAGCTTCCAGCTCTTCCTCACCGACGAGGGGCTGGCCATCCACCAGCATGCGGAGGCCATCATGTCACGCGTGCATGACGAGTTGTTT
GCCCCGCTCACCCCGGTGGAACAGGCCACCCTGGTGCATCTCCTCGACCAGTGCCTGGCCGCGCAACCGCTTGAGGATATTTAA


Model Type: protein variant model

Model Definition: Protein Variant Models (PVM) perform a similar search as Protein Homolog Models (PHM), i.e. detect protein sequences based on their similarity to a curated reference sequence, but secondarily screen query sequences for curated sets of mutations to differentiate them from antibiotic susceptible wild-type alleles. PVMs are designed to detect AMR acquired via mutation of house-keeping genes or antibiotic targets, e.g. a mutated gyrase resistant to aminocoumarin antibiotics. PVMs include a protein reference sequence (often from antibiotic susceptible wild-type alleles), a curated bit-score cut-off, and mapped resistance variants. Mapped resistance variants may include any or all of single point mutations, insertions, or deletions curated from the scientific literature. A Strict RGI match has a BLASTP bit-score above the curated BLASTP cutoff value and contains at least one curated mutation from amongst the mapped resistance variants, while a Loose RGI match has a bit-score less than the curated BLASTP bit-score cut-off but still contains at least one curated mutation from amongst the mapped resistance variants.

Bit-score Cut-off (blastP): 270

PubMed: mutation data hand curated from the scientific literature, evaluated as conferring resistance (R). CRyPTIC: mutation data acquired from the CRyPTIC catalog, evaluated as resistant (R), susceptible (S), or undetermined (U). ReSeqTB: mutation data acquired from the ReSeqTB catalog, evaluated as conferring resistance (Minimal, Moderate, High), not conferring resistance (None), or Indeterminate. WHO: mutation data acquired from the WHO 2023 catalog, evaluated as resistant (R), susceptible (S), or undetermined (U).

MutationMutation typePubMed
L35Ternonsense mutationPMID:12727072

>gb|AAG03813.1|-|mexR [Pseudomonas aeruginosa PAO1]
MNYPVNPDLMPALMAVFQHVRTRIQSELDCQRLDLTPPDVHVLKLIDEQRGLNLQDLGRQ
MCRDKALITRKIRELEGRNLVRRERNPSDQRSFQLFLTDEGLAIHQHAEAIMSRVHDELF
APLTPVEQATLVHLLDQCLAAQPLEDI



>gb|AE004091.2|-|471306-471749|mexR [Pseudomonas aeruginosa PAO1]
ATGAACTACCCCGTGAATCCCGACCTGATGCCCGCGCTGATGGCGGTCTTCCAGCATGTGCGGACGCGCATCCAGAGCGAGCTCGATTGC
CAGCGACTCGACCTGACCCCGCCCGACGTCCATGTATTGAAGCTTATCGACGAACAACGCGGGCTGAACCTGCAGGACCTGGGACGCCAG
ATGTGCCGCGACAAGGCACTGATCACCCGGAAGATCCGCGAGCTGGAGGGAAGAAACCTGGTCCGCCGCGAGCGCAACCCCAGCGACCAG
CGCAGCTTCCAGCTCTTCCTCACCGACGAGGGGCTGGCCATCCACCAGCATGCGGAGGCCATCATGTCACGCGTGCATGACGAGTTGTTT
GCCCCGCTCACCCCGGTGGAACAGGCCACCCTGGTGCATCTCCTCGACCAGTGCCTGGCCGCGCAACCGCTTGAGGATATTTAA

Curator Acknowledgements
Curator Description Most Recent Edit