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 β-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

Prevalence of aac(6')-Ib-cr plasmid-mediated and chromosome-encoded fluoroquinolone resistance in Enterobacteriaceae in Italy

“…qnr and qepA , by PCR amplification and sequencing using published procedures [3]. None of these was found in the aac(6')-Ib-cr -positive samples, while 5 out of 9 aac(6')-Ib -positive strains presented the qnrB19 gene, indicating that just one of the reported plasmid-encoded mechanisms of FQ resistance was acquired/maintained in the clinical isolates.…”

“…Plasmid localization of the aac(6')-Ib-cr gene was further confirmed by successful transformation into E. coli Top10 strain of all 16 sample-plasmid DNA, extracted according the Kieser protocol [10]. Transferability of the resistance gene of three clinical isolates was tested by conjugation in a kanamycin/sodium azide resistant E. coli J53 strain [3]. All three samples were successfully conjugated.…”

KPC-mediated resistance in Klebsiella pneumoniae in two hospitals in Padua, Italy, June 2009-December 2011: massive spreading of a KPC-3-encoding plasmid and involvement of non-intensive care units

“…Resistance genes ( bla KPC bla TEM bla SHV bla CTX-M bla VIM bla IMP bla NMC-IMI bla SME bla SPM bla OXA-1 bla OXA-9 bla OXA-48 bla OXA-58 bla OXA-23 bla OXA-24 bla OXA-51 bla OXA-143 ) were detected by PCR and sequencing [19,20]. Positive PCR products were sequenced with an ABI3730 sequencer (Applied Biosystems) and sequences compared with those from GenBank (http://www.ncbi.nlm.nih.gov/blast/).…”

“…Isolates with the same pulsotype were classified as a clone. ERIC-PCR was performed using reported primers ERIC1 and ERIC2 [20]. …”

Transfer of KPC-2 Carbapenemase from Klebsiella pneumoniae to Escherichia coli in a Patient: First Case in Europe

“…The three strains were further analyzed for the presence of additional mechanisms of resistance to ␤-lactams. In particular, the bla genes for TEM-, SHV-, CTX-, IMP-, VIM-, NMC/IMI-, SME-, SPM-, and OXA-type carbapenemases and ␤-lactamases were tested by PCR amplification and sequencing (21). The bla TEM-1 and bla OXA-9 genes of class A and D ␤-lactamases, respectively (2), were found in both K. pneumoniae and E. coli; the former also contained the bla VIM-1 gene, while P. aeruginosa did not present any of the ␤-lactamases tested for.…”