title: [Characteristic of fluoroquinolone resistant clinical isolates of K. pneumoniae, P. mirabilis and E. coli producing ESBL and AmpC beta-lactamases].
abstract: BACKGROUND
  Extended-spectrum beta-lactamases (ESBLs) are the predominant mechanism for acquired antibiotic resistance in Enterobacteriaceae. During the past few years, increasing occurrence of plasmid-mediated AmpC beta-lactamases (pAmpCs) particularly in K. pneumonia, P. mirabilis and E. coli was reported. Therefore, the aim of our study was to analyse of the diversity of plasmid-mediated beta-lactamases such as pAmpCs and ESBLs among clinical K. pneumonia, P. mirabilis and E. coli strains in Poland.
  
  
  METHODS
  A total of 19 clinical Enterobacteriaceae strains (E. coli, n = 9; K. pneumoniae, n = 7; P. mirabilis, n = 3) resistant to third-generation cephalosporin were selected from collection of fluoroquinolone resistant isolates recovered during a 6-months period in regular hospital in Warsaw, Poland. ESBLs and AmpCs were detected by using phenotypic methods: double-disc tests (DDSTs), MAST ID D68C test, sensitivity to cefoxitin, disk potentiation test (DPT) and Tris-EDTA test. Polymerase chain reaction (PCR) amplification of the bla(AmpC), bla(CTM-M), bla(TEM), and bla(SHV), genes. PCR-products for these genes were sequenced. To determine the possible clonality of the tested isolates PFGE with the XbaI was performed.
  
  
  RESULTS
  Nine of 19 fluoroquinolone-resistant strains tested produced extended-spectrum beta-lactamases of TEM, SHV and CTX-M families. These ESBLs were most commonly detected in E. coli. AmpC beta-lactamases were produced by 6 tested strains, including 3 isolates of P. mirabilis. The AmpC found in our study belonged to CMY and DHA families, Furthermore, 4 isolates of K. pneumoniae were found to co-produce both ESBL and AmpC beta-lactamases. XbaI-PFGE profiles pointed significant differences of tested strains.
  
  
  CONCLUSIONS
  Horizontal transfer of genes encoding for acquired beta-lactamases such ESBL and AmpC seem to play primary role in dissemination of these resistance traits among fluoroquinolone-resistant clinical strains of Enterobacteriaceae in Poland.
authors.affiliation: Zakład Bakteriologii Narodowego Instytutu Zdrowia Publicznego - Państwowego Zakładu Higieny w Warszawie. mrzeczkowska@pzh.gov.pl
authors.forename: Magdalena
authors.initials: M
authors.lastname: Rzeczkowska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piekarska
authors.forename: Rafał
authors.initials: R
authors.lastname: Gierczyński
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D002511:Cephalosporins / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D024841:Fluoroquinolones / Q000494:pharmacology*; D007711:Klebsiella pneumoniae / Q000235:genetics / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000378:metabolism*; D011513:Proteus mirabilis / Q000235:genetics / Q000378:metabolism*; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D002511:Cephalosporins; D024841:Fluoroquinolones; C048795:AmpC beta-lactamases; D001618:beta-Lactamases