Accession ARO:3000823
CARD Short NameramA
DefinitionRamA (resistance antibiotic multiple) is a positive regulator of AcrAB-TolC and leads to high level multidrug resistance in Klebsiella pneumoniae, Salmonella enterica, and Enterobacter aerugenes, increasing the expression of both the mar operon as well as AcrAB. RamA also decreases OmpF expression.
AMR Gene FamilyGeneral Bacterial Porin with reduced permeability to beta-lactams, resistance-nodulation-cell division (RND) antibiotic efflux pump
Drug Classtetracycline antibiotic, cephalosporin, cephamycin, carbapenem, monobactam, penem, phenicol antibiotic, rifamycin antibiotic, penam, glycylcycline, disinfecting agents and antiseptics, fluoroquinolone antibiotic
Resistance Mechanismreduced permeability to antibiotic, antibiotic efflux
Efflux Componentefflux pump complex or subunit conferring antibiotic resistance
Efflux Regulatorprotein(s) and two-component regulatory system modulating antibiotic efflux
Resistomes with Sequence VariantsEnterobacter asburiaeg+wgs, Enterobacter chengduensisg+wgs, Enterobacter cloacaeg+wgs, Enterobacter hormaecheig+p+wgs, Enterobacter kobeiwgs, Enterobacter roggenkampiig+wgs, Klebsiella pneumoniaewgs, Serratia marcescenswgs, Xanthomonas oryzaewgs
Classification32 ontology terms | Show
Parent Term(s)3 ontology terms | Show

Chollet R, et al. 2004. Antimicrob Agents Chemother 48(7): 2518-2523. RamA is an alternate activator of the multidrug resistance cascade in Enterobacter aerogenes. (PMID 15215103)

Nikaido E, et al. 2008. J Biol Chem 283(35): 24245-24253. AcrAB multidrug efflux pump regulation in Salmonella enterica serovar Typhimurium by RamA in response to environmental signals. (PMID 18577510)

George AM, et al. 1995. Microbiology 141(PT 8): 1909-1920. Multidrug resistance in Klebsiella pneumoniae: a novel gene, ramA, confers a multidrug resistance phenotype in Escherichia coli. (PMID 7551053)

Schneiders T, et al. 2003. Antimicrob Agents Chemother 47(9): 2831-2837. Role of AcrR and ramA in fluoroquinolone resistance in clinical Klebsiella pneumoniae isolates from Singapore. (PMID 12936981)


Prevalence of ramA 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 homolog model (view sequences)

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GI
Enterobacter asburiae100%0%86.81%0%
Enterobacter chengduensis100%0%90.91%0%
Enterobacter cloacae86.36%0%72.73%0%
Enterobacter hormaechei93.45%0.34%74.28%0%
Enterobacter kobei0%0%84.43%0%
Enterobacter roggenkampii96.15%0%73.33%0%
Escherichia coli0%0%0%0%
Klebsiella pneumoniae0%0%0.09%0%
Serratia marcescens0%0%0.15%0%
Xanthomonas oryzae0%0%0.34%0%
Show Perfect Only

Detection Models

Model Type: protein homolog model

Model Definition: The protein homolog model is an AMR detection model. Protein homolog models detect a protein sequence based on its similarity to a curated reference sequence. A protein homolog model has only one parameter: a curated BLASTP bitscore cutoff for determining the strength of a match. Protein homolog model matches to reference sequences are categorized on three criteria: perfect, strict and loose. A perfect match is 100% identical to the reference sequence along its entire length; a strict match is not identical but the bitscore of the matched sequence is greater than the curated BLASTP bitscore cutoff. Loose matches are other sequences with a match bitscore less than the curated BLASTP bitscore.

Bit-score Cut-off (blastP): 230

>gb|AFK13828.1|+|ramA [Enterobacter cloacae]

>gb|JQ727668.1|+|1-375|ramA [Enterobacter cloacae]