dfrA21

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Accession	ARO:3003017
CARD Short Name	dfrA21
Definition	dfrA21 is an integron-encoded dihydrofolate reductase found in Salmonella enterica.
AMR Gene Family	trimethoprim resistant dihydrofolate reductase dfr
Drug Class	diaminopyrimidine antibiotic
Resistance Mechanism	antibiotic target replacement
Resistomes with Perfect Matches	Aeromonas veronii^p, Citrobacter freundii^wgs, Citrobacter portucalensis^wgs, Enterobacter hormaechei^p+wgs, Enterobacter kobei^wgs, Enterobacter roggenkampii^wgs, Escherichia coli^p+wgs, Klebsiella michiganensis^wgs, Klebsiella pneumoniae^wgs, Klebsiella quasipneumoniae^p+wgs, Pseudomonas aeruginosa^wgs, Salmonella enterica^wgs
Resistomes with Sequence Variants	Aeromonas veronii^p, Citrobacter freundii^wgs, Citrobacter portucalensis^wgs, Enterobacter hormaechei^p+wgs, Enterobacter kobei^wgs, Enterobacter roggenkampii^wgs, Escherichia coli^p+wgs, Klebsiella michiganensis^wgs, Klebsiella pneumoniae^wgs, Klebsiella quasipneumoniae^p+wgs, Pseudomonas aeruginosa^wgs, Salmonella enterica^wgs
Classification	9 ontology terms \| Show + process or component of antibiotic biology or chemistry + mechanism of antibiotic resistance + determinant of antibiotic resistance + antibiotic molecule + antibiotic target replacement [Resistance Mechanism] + antibiotic target replacement protein + diaminopyrimidine antibiotic [Drug Class] + antibiotic resistant dihydrofolate reductase + trimethoprim [Antibiotic]
Parent Term(s)	3 ontology terms \| Show + confers_resistance_to_antibiotic trimethoprim [Antibiotic] + derives_from antibiotic sensitive dihydrofolate reductase + trimethoprim resistant dihydrofolate reductase dfr [AMR Gene Family]
Publications	Bouallegue-Godet O, et al. 2005. J Clin Microbiol 43(3): 1037-1044. Nosocomial outbreak caused by Salmonella enterica serotype Livingstone producing CTX-M-27 extended-spectrum beta-lactamase in a neonatal unit in Sousse, Tunisia. (PMID 15750057)

Resistomes

Prevalence of dfrA21 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 homolog model (view sequences)

Species	NCBI Chromosome	NCBI Plasmid	NCBI WGS	NCBI GI	GRDI-AMR2
Aeromonas veronii	0%	1.54%	0%	0%	0%
Aeromonas veronii	0%	1.54%	0%	0%	0%
Citrobacter freundii	0%	0%	0.19%	0%	0%
Citrobacter freundii	0%	0%	0.19%	0%	0%
Citrobacter portucalensis	0%	0%	0.9%	0%	0%
Citrobacter portucalensis	0%	0%	0.9%	0%	0%
Enterobacter hormaechei	0%	0.13%	0.6%	0%	0%
Enterobacter hormaechei	0%	0.13%	0.6%	0%	0%
Enterobacter kobei	0%	0%	1.75%	0%	0%
Enterobacter kobei	0%	0%	1.75%	0%	0%
Enterobacter roggenkampii	0%	0%	0.36%	0%	0%
Enterobacter roggenkampii	0%	0%	0.36%	0%	0%
Escherichia coli	0%	0.01%	0.03%	0%	0%
Escherichia coli	0%	0.01%	0.01%	0%	0%
Klebsiella michiganensis	0%	0%	0.27%	0%	0%
Klebsiella michiganensis	0%	0%	0.27%	0%	0%
Klebsiella pneumoniae	0%	0%	0.06%	0%	0%
Klebsiella pneumoniae	0%	0%	0.06%	0%	0%
Klebsiella quasipneumoniae	0%	0.42%	0.13%	0%	0%
Klebsiella quasipneumoniae	0%	0.42%	0.13%	0%	0%
Pseudomonas aeruginosa	0%	0%	0.11%	0%	0%
Pseudomonas aeruginosa	0%	0%	0.11%	0%	0%
Salmonella enterica	0%	0%	0.01%	0%	0%
Salmonella enterica	0%	0%	0.01%	0%	0%

Show Perfect Only

Detection Models

protein homolog model

Model Type: protein homolog model

Model Definition: Protein Homolog Models (PHM) detect protein sequences based on their similarity to a curated reference sequence, using curated BLASTP bitscore cut-offs. Protein Homolog Models apply to all genes that confer resistance through their presence in an organism, such as the presence of a beta-lactamase gene on a plasmid. PHMs include a reference sequence and a bitscore cut-off for detection using BLASTP. A Perfect RGI match is 100% identical to the reference protein sequence along its entire length, a Strict RGI match is not identical but the bit-score of the matched sequence is greater than the curated BLASTP bit-score cutoff, Loose RGI matches have a bit-score less than the curated BLASTP bit-score cut-off.

Bit-score Cut-off (blastP): 300

Protein
DNA

>gb|CAP69659.1|+|dfrA21 [Salmonella enterica subsp. enterica serovar Bredeney]
MNPESVRIYLVAAMGANRVIGNGPDIPWKIPGEQKIFRRLTESKVVVMGRKTFESIGKPLPNRHTVVLSRQARYSAPGCAVVSTLSQAIA
IAAEHGKELYVAGGAEVYALALPHANGVFLSEVHQTFEGDAFFPVLNAAEFEVVSSETIQGTITYTHSVYARRNG

>gb|AM932669.1|+|106-603|dfrA21 [Salmonella enterica subsp. enterica serovar Bredeney]
ATGAACCCGGAATCGGTCCGCATTTATCTGGTCGCTGCCATGGGTGCCAATCGGGTTATTGGCAATGGTCCCGATATCCCCTGGAAAATC
CCAGGTGAGCAGAAGATTTTTCGCAGGCTCACCGAGAGCAAAGTGGTCGTTATGGGCCGCAAGACATTTGAGTCCATAGGCAAGCCCTTA
CCAAACCGCCACACAGTGGTGCTCTCGCGCCAAGCTCGTTATAGCGCTCCTGGTTGTGCAGTTGTTTCAACGCTGTCACAGGCTATCGCC
ATCGCAGCCGAACACGGCAAAGAACTCTACGTAGCCGGCGGAGCCGAGGTATATGCGCTGGCGCTACCGCATGCCAACGGCGTCTTTCTA
TCTGAGGTACATCAAACCTTTGAGGGTGACGCCTTCTTCCCAGTGCTTAACGCAGCAGAATTCGAGGTTGTCTCATCCGAAACCATTCAA
GGCACAATCACGTACACGCACTCCGTCTATGCGCGTCGTAACGGCTAA

Curator Acknowledgements

Curator	Description	Most Recent Edit

dfrA21

Prevalence: protein homolog model (view sequences)

Graph