Campos, Maria JorgePalomo, GonzaloHormeño, LorenaRodrigues, AméricoSánchez-Benito, RosarioPíriz, SegundoQuesada, Alberto2025-09-262025-09-262015-02Campos MJ, Palomo G, Hormeño L, Patrocínio Rodrigues A, SánchezBenito R, Píriz S, Quesada A. 2015. Detection of QnrB54 and its novel genetic context in Citrobacter freundii isolated from a clinical case. Antimicrob Agents Chemother 59:1375–1376. doi:10.1128/AAC.03895-140066-48041098-6596http://hdl.handle.net/10400.8/14132Document type - Letter to the editor.Accepted manuscript posted online 15 December 2014.LETTER Quinolone resistance in Enterobacteriaceae is mediated by mutations in the quinolone resistance-determining regions (QRDR) of topoisomerase genes and/or by plasmid-mediated quinolone resistance determinants (PMQR) such as the qnr genes encoding pentapeptide repeat proteins (1). The qnrB family is represented by 80 different alleles (http://www.lahey.org/qnrStudies/); most of them originated from Citrobacter strains and spread to other Enterobacteriaceae species (2). This work describes the identification of a new allele of the quinolone resistance protein QnrB, QnrB54, in a human clinical isolate of Citrobacter freundii detected in Spain.engCitrobacter freundiiDrug ResistanceHumansMolecular Sequence DataQuinolonesjournal article10.1128/aac.03895-14