Accession ARO:3002869
DefinitiondfrK is a plasmid-encoded dihydrofolate reductase found in Staphylococcus aureus
AMR Gene Familytrimethoprim resistant dihydrofolate reductase dfr
Drug Classdiaminopyrimidine antibiotic
Resistance Mechanismantibiotic target replacement
Classification10 ontology terms | Show
Parent Term(s)2 ontology terms | Show

Kadlec K, et al. 2012. J Antimicrob Chemother 67(10): 2342-2345. Unusual small plasmids carrying the novel resistance genes dfrK or apmA isolated from methicillin-resistant or -susceptible staphylococci. (PMID 22718530)


Prevalence of dfrK among the sequenced genomes, plasmids, and whole-genome shotgun assemblies available at NCBI for 82 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
Enterococcus faecium0%0%0.21%
Staphylococcus aureus0.47%0%2.38%
Staphylococcus pseudintermedius0%0%0.51%
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|CBL80435.1|+|dfrK [Staphylococcus aureus]

>gb|FN812951|+|1-492|dfrK [Staphylococcus aureus]