Accession ARO:3003019
DefinitiondfrA23 is an integron-encoded dihydrofolate reductase found in Salmonella enterica
AMR Gene Familytrimethoprim resistant dihydrofolate reductase dfr
Drug Classdiaminopyrimidine antibiotic
Resistance Mechanismantibiotic target replacement
ResistomesEscherichia colip+wgs, Klebsiella pneumoniaep+wgs, Providencia rettgeriwgs, Pseudomonas aeruginosawgs, Salmonella entericap+wgs, Vibrio choleraewgs
Classification9 ontology terms | Show
Parent Term(s)2 ontology terms | Show

Villa L, et al. 2005. Antimicrob Agents Chemother 49(3): 1194-1197. Integrons and transposons on the Salmonella enterica serovar typhimurium virulence plasmid. (PMID 15728925)


Prevalence of dfrA23 among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI for 88 important pathogens (see methodological details and complete list of analyzed pathogens). Values reflect percentage of genomes, plasmids, 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 WGS
Escherichia coli0%0.01%0.04%
Klebsiella pneumoniae0%0.07%0.1%
Providencia rettgeri0%0%6.25%
Pseudomonas aeruginosa0%0%0.02%
Salmonella enterica0%0.63%0.55%
Vibrio cholerae0%0%1.62%
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): 300

>gb|CAG34233.2|-|dfrA23 [Salmonella enterica subsp. enterica serovar Typhimurium]

>gb|AJ746361|-|6743-7303|dfrA23 [Salmonella enterica subsp. enterica serovar Typhimurium]