title: Phylogenetic lineages, clones and β-lactamases in an international collection of Klebsiella oxytoca isolates non-susceptible to expanded-spectrum cephalosporins.
abstract: OBJECTIVE
  The objective of this study was to examine Klebsiella oxytoca clonal and phylogenetic diversity, based on an international collection of carriage isolates non-susceptible to expanded-spectrum cephalosporins (ESCs).
  
  
  METHODS
  The study material comprised 68 rectal carriage K. oxytoca isolates non-susceptible to ESCs recovered in 2008-11 from patients in 14 hospitals across Europe and Israel. ESC resistance was tested phenotypically; genes encoding ESBLs, AmpC cephalosporinases and carbapenemases were amplified and sequenced. The isolates were typed by PFGE and MLST, followed by sequencing of blaOXY genes.
  
  
  RESULTS
  MLST and PFGE distinguished 34 STs and 47 pulsotypes among the isolates, respectively. Six STs were split into several pulsotypes each. Five STs were more prevalent (n = 2-9) and occurred in several countries each, including ST2, ST9 and ST141, which belong to a growing international clonal complex (CC), CC2. Four phylogenetic lineages were distinguished, each with another type of chromosomal OXY-type β-lactamase. Three of these, with OXY-1/-5, OXY-2 types and OXY-4, corresponded to previously described phylogroups KoI, KoII and KoIV, respectively. A single isolate from Israel represented a distinct lineage with a newly defined OXY-7 type. The phylogroups showed interesting differences in mechanisms of ESC resistance; KoI strains rarely overexpressed the OXY enzymes but commonly produced ESBLs, whereas KoII strains often were OXY hyperproducers and carried ESBLs much less frequently. AmpCs (DHA-1) and carbapenemases (VIM-1) occurred sporadically.
  
  
  CONCLUSIONS
  The study confirmed the high genetic diversity of the collection of K. oxytoca ESC-non-susceptible isolates, composed of phylogroups with distinct types of OXY-type β-lactamases, and revealed some STs of broad geographical distribution.
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland radek@cls.edu.pl.
authors: R
authors: R
authors: Izdebski
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland.
authors: J
authors: J
authors: Fiett
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland.
authors: P
authors: P
authors: Urbanowicz
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland.
authors: A
authors: A
authors: Baraniak
authors: Department of Medical Microbiology and Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: L P G
authors: LP
authors: Derde
authors: Department of Medical Microbiology and Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors: M J M
authors: MJ
authors: Bonten
authors: Division of Epidemiology and Preventive Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
authors: Y
authors: Y
authors: Carmeli
authors: Department of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
authors: H
authors: H
authors: Goossens
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland.
authors: W
authors: W
authors: Hryniewicz
authors: Service de reanimation médicale, INSERM, U957 & Université Paris-Est, Créteil, France.
authors: C
authors: C
authors: Brun-Buisson
authors: Microbial Evolutionary Genomics, Institut Pasteur, Paris, France.
authors: S
authors: S
authors: Brisse
authors: Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland.
authors: M
authors: M
authors: Gniadkowski
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology; D002511:Cephalosporins / Q000494:pharmacology*; D005060:Europe / Q000453:epidemiology; D005243:Feces / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007557:Israel / Q000453:epidemiology; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology*; D041121:Klebsiella oxytoca / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases