title: Characterisation of qnr plasmid-mediated quinolone resistance in Enterobacteriaceae from Italy: association of the qnrB19 allele with the integron element ISCR1 in Escherichia coli.
abstract: The spread of plasmid-mediated quinolone resistance determinants (qnr-like determinants) was evaluated in a collection of 232 ciprofloxacin-resistant or extended-spectrum beta-lactamase (ESBL)-producing enterobacterial isolates recovered between November 2007 and May 2008 at Padua University Hospital, Italy. qnr genes were mainly found in Klebsiella pneumoniae (68%) and to a lesser extent in Escherichia coli (5.1%). Among the qnrA1, qnrS1 and qnrB19 alleles found, the latter was by far the most frequent. Genetic environment analysis revealed that one qnrB19 gene in E. coli was embedded in an ISCR1 complex class 1 integron. All other qnrB19 genes were flanked by an ISEcp1C region as part of the Tn2012 transposon. qnrA1- and qnrS1-containing strains were not clonally related. Both topoisomerase II mutations and ESBL (mainly SHV-12, TEM-1 and TEM-150 types) were present in most of the qnr-positive strains. qnrB19 is extremely frequent in K. pneumoniae isolates from Italy. In addition, association of qnrB19 with the ISCR1 mobile element in E. coli suggests a broad distribution of this resistance gene in the near future.
authors.affiliation: Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, via Gabelli 63, 35121 Padua, Italy. sara.richter@unipd.it
authors.forename: Sara N
authors.initials: SN
authors.lastname: Richter
authors.forename: Ilaria
authors.initials: I
authors.lastname: Frasson
authors.forename: Cristina
authors.initials: C
authors.lastname: Bergo
authors.forename: Riccardo
authors.initials: R
authors.lastname: Manganelli
authors.forename: Antonietta
authors.initials: A
authors.lastname: Cavallaro
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palù
mesh_terms: D000483:Alleles; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects*; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D020071:Interspersed Repetitive Sequences; D007558:Italy; D008297:Male; D008969:Molecular Sequence Data; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; C485385:Qnr protein, Klebsiella pneumoniae; D015363:Quinolones