| Accession | ARO:3000506 |
| Synonym(s) | nalB |
| CARD Short Name | MexR |
| Definition | MexR is the repressor of the MexRAB-OprM operon. Mutant forms of mexR result in up-regulation of efflux pump system MexAB-OprM. |
| AMR Gene Family | resistance-nodulation-cell division (RND) antibiotic efflux pump |
| Drug Class | peptide antibiotic, sulfonamide antibiotic, diaminopyrimidine antibiotic, carbapenem, macrolide antibiotic, monobactam, cephalosporin, penam, phenicol antibiotic, aminocoumarin antibiotic, tetracycline antibiotic, fluoroquinolone antibiotic, penem, cephamycin |
| Resistance Mechanism | antibiotic efflux, antibiotic target alteration |
| Efflux Component | efflux pump complex or subunit conferring antibiotic resistance |
| Efflux Regulator | protein(s) and two-component regulatory system modulating antibiotic efflux |
| Resistomes with Sequence Variants | Acinetobacter baumanniiwgs, Enterobacter hormaecheiwgs, Klebsiella pneumoniaewgs, Pseudomonas aeruginosag+p+wgs, Pseudomonas fluorescensg, Stenotrophomonas maltophiliawgs |
| Classification | 48 ontology terms | Show + process or component of antibiotic biology or chemistry + antibiotic molecule + peptide antibiotic [Drug Class] + beta-lactam antibiotic + lipopeptide antibiotic + mechanism of antibiotic resistance + determinant of antibiotic resistance + polymyxin antibiotic + cephem + sulfonamide antibiotic [Drug Class] + diaminopyrimidine antibiotic [Drug Class] + antibiotic efflux [Resistance Mechanism] + carbapenem [Drug Class] + efflux pump complex or subunit conferring antibiotic resistance [Efflux Component] + colistin + macrolide antibiotic [Drug Class] + trimethoprim [Antibiotic] + monobactam [Drug Class] + cephalosporin [Drug Class] + penam [Drug Class] + phenicol antibiotic [Drug Class] + aminocoumarin antibiotic [Drug Class] + tetracycline antibiotic [Drug Class] + fluoroquinolone antibiotic [Drug Class] + sulfamethoxazole [Antibiotic] + antibiotic mixture + antibiotic target alteration [Resistance Mechanism] + penem [Drug Class] + colistin A [Antibiotic] + panipenem [Antibiotic] + ciprofloxacin [Antibiotic] + aztreonam [Antibiotic] + colistin B [Antibiotic] + trimethoprim-sulfamethoxazole [Antibiotic] + ceftazidime [Antibiotic] + azithromycin [Antibiotic] + ampicillin [Antibiotic] + novobiocin [Antibiotic] + resistance-nodulation-cell division (RND) antibiotic efflux pump [AMR Gene Family] + erythromycin [Antibiotic] + chloramphenicol [Antibiotic] + tetracycline [Antibiotic] + cephamycin [Drug Class] + mutation conferring antibiotic resistance + meropenem [Antibiotic] + ceftriaxone [Antibiotic] + antibiotic resistant gene variant or mutant + MexAB-OprM |
| Parent Term(s) | 5 ontology terms | Show + protein(s) and two-component regulatory system modulating antibiotic efflux [Efflux Regulator] + regulates MexAB-OprM + mutant efflux regulatory protein conferring antibiotic resistance + part_of MexAB-OprM with prematurely terminated MexR conferring resistance to meropenem and ciprofloxacin + part_of MexAB-OprM with MexR mutations confers resistance to multiple antibiotics |
| 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) |
Prevalence of MexR among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI or IslandViewer for 377 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).
| Species | NCBI Chromosome | NCBI Plasmid | NCBI WGS | NCBI GI |
|---|---|---|---|---|
| Acinetobacter baumannii | 0% | 0% | 0.02% | 0% |
| Enterobacter hormaechei | 0% | 0% | 0.05% | 0% |
| Klebsiella pneumoniae | 0% | 0% | 0.01% | 0% |
| Pseudomonas aeruginosa | 100% | 0.64% | 75.28% | 0% |
| Pseudomonas fluorescens | 2.86% | 0% | 0% | 0% |
| Stenotrophomonas maltophilia | 0% | 0% | 0.17% | 0% |
| Species | NCBI Chromosome | NCBI Plasmid | NCBI WGS | NCBI GI |
|---|---|---|---|---|
| No prevalence data | ||||
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
Legend:
Published Variants:
| PMID: 14526032 | L45P I46N L57R L57P T69I I72N L75P L75R R83C R91H R91C H107P |
| PMID: 12727072 | N53D |
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
Legend:
Published Variants:
PMID in progress (nonsense): L35STOP
| PMID: 14526032 | L45P I46N L57R L57P T69I I72N L75P L75R R83C R91H R91C H107P |
| PMID: 12727072 | N53D |
