title: Carbapenem-hydrolyzing oxacillinase, OXA-48, persists in Klebsiella pneumoniae in Istanbul, Turkey.
abstract: BACKGROUND
  Two OXA-48-producing Klebsiella pneumoniae isolates (KP-4936 and KP-154488) were analyzed.
  
  
  METHODS
  Minimum inhibitory concentrations were determined using agar dilution and E-test, beta-lactamase production by phenotypic tests (E-test MBL and ESBL, isoelectric focusing, and bioassay) and molecular methods (PCR, RAPD-PCR, sequencing, plasmid analysis, and conjugation).
  
  
  RESULTS
  Isolates were resistant to all beta-lactams, including carbapenems. PCR and sequencing identified bla(OXA-48) in both isolates and the transconjugant. KP-4936 harbored bla(TEM-1) (pI 5.4) and bla(CTX-M-15) genes (pI 8.6), while KP-154488 was positive for bla(TEM-1) (pI 5.4), bla(CTX-M-15) (pI 8.9), and bla(SHV2a) (pI 7.6), in addition. The enzyme with a pI of 7.2 hydrolyzed imipenem according to a bioassay result. Plasmids (70 and 140 kb) from KP-4936 were transferred by conjugation. RAPD-PCR found no clonal relationship between the two strains.
  
  
  CONCLUSIONS
  Carbapenem resistance may spread among Enterobacteriaceae via the transferable enzyme OXA-48.
authors.affiliation: Department of Microbiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Zerrin
authors.initials: Z
authors.lastname: Aktaş
authors.forename: Ciğdem Bal
authors.initials: CB
authors.lastname: Kayacan
authors.forename: Ines
authors.initials: I
authors.lastname: Schneider
authors.forename: Bariş
authors.initials: B
authors.lastname: Can
authors.forename: Kenan
authors.initials: K
authors.lastname: Midilli
authors.forename: Adolf
authors.initials: A
authors.lastname: Bauernfeind
mesh_terms: D015780:Carbapenems / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D006868:Hydrolysis; D007710:Klebsiella Infections / Q000188:drug therapy / Q000201:enzymology / Q000453:epidemiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000302:isolation & purification; D014421:Turkey / Q000453:epidemiology; D018440:beta-Lactam Resistance / Q000187:drug effects* / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000737:chemistry*
chemical_list: D015780:Carbapenems; D001618:beta-Lactamases; C108449:oxacillinase