Accession ARO:3002780
CARD Short NameQnrB68
DefinitionQnrB68 is a plasmid-mediated quinolone resistance protein found in Citrobacter braakii.
AMR Gene Familyquinolone resistance protein (qnr)
Drug Classfluoroquinolone antibiotic
Resistance Mechanismantibiotic target protection
Resistomes with Sequence VariantsBifidobacterium bifidumwgs, Enterobacter cloacaewgs, Enterobacter hormaecheiwgs, Enterococcus faeciumwgs, Escherichia coliwgs, Klebsiella pneumoniaewgs, Salmonella entericawgs, Serratia marcescenswgs
Classification14 ontology terms | Show
Parent Term(s)2 ontology terms | Show
+ quinolone resistance protein (qnr) [AMR Gene Family]
+ confers_resistance_to_antibiotic ciprofloxacin [Antibiotic]

Halova D, et al. 2014. Antimicrob Agents Chemother 58(2): 1257-1258. Plasmid-mediated quinolone resistance genes in Enterobacteriaceae from American crows: high prevalence of bacteria with variable qnrB genes. (PMID 24247140)


Prevalence of QnrB68 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).

Prevalence: protein homolog model (view sequences)

SpeciesNCBI ChromosomeNCBI PlasmidNCBI WGSNCBI GI
Bifidobacterium bifidum0%0%0.98%0%
Enterobacter cloacae0%0%0.36%0%
Enterobacter hormaechei0%0%0.05%0%
Enterococcus faecium0%0%0.04%0%
Escherichia coli0%0%0.01%0%
Klebsiella pneumoniae0%0%0.01%0%
Salmonella enterica0%0%0.01%0%
Serratia marcescens0%0%0.14%0%
Show Perfect Only

Detection Models

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): 400

>gb|AGL43629.1|+|QnrB68 [Citrobacter braakii]

>gb|KC580657.1|+|1-645|QnrB68 [Citrobacter braakii]