title: Polyclonal spread of bla(OXA-23) and bla(OXA-58) in Acinetobacter baumannii isolates from Argentina.
abstract: BACKGROUND
  In order to study the enzymatic carbapenem resistance mechanisms in Acinetobacter baumannii isolates from Argentina, we performed molecular characterization on 41 epidemiologically unrelated strains isolated from 1995 to 2006 with diminished susceptibilities to imipenem and meropenem.
  
  
  METHODS
  Acinetobacter baumannii isolates were identified with the ARDRA technique. The total genomic DNA was used to detect each carbapenem beta-lactamase gene described so far in this species and those insertion sequences usually associated to carbapenem beta-lactamase genes (ISAba1, 2, 3, 4 and IS18) by the PCR technique with specific primers.
  
  
  RESULTS
  26 out of 41 Acinetobacter baumannii isolates with diminished susceptibilities to carbapenems harboured the bla(OXA-23) gene. The bla(OXA-58) was detected in 13 out of 41 isolates. ISAba1 was always located upstream bla(OXA-23). All isolates containing the bla(OXA-58) gene showed ISAba3 downstream of the carbapenemase, while 4 isolates had a second copy of the ISAba3 upstream of the gene.
  
  
  CONCLUSIONS
  Enzymatic carbapenem resistance in Acinetobacter baumannii was found in 88% of 41 non-epidemiologically-related strains mediated by the polyclonal spread of the bla(OXA-23) and bla(OXA-58) genes. The genetic structures surrounding the oxacillinase genes found in our bacterial isolates revealed a particular epidemiology in our geographical region. This data suggests the need of local molecular surveillance to help control multirresistance Acinetobacter baumannii infections.
authors.affiliation: Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155. Buenos Aires, Argentina.
authors.forename: Andrea Karina
authors.initials: AK
authors.lastname: Merkier
authors.forename: Mariana
authors.initials: M
authors.lastname: Catalano
authors.forename: María Soledad
authors.initials: MS
authors.lastname: Ramírez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Quiroga
authors.forename: Betina
authors.initials: B
authors.lastname: Orman
authors.forename: Laura
authors.initials: L
authors.lastname: Ratier
authors.forename: Angela
authors.initials: A
authors.lastname: Famiglietti
authors.forename: Carlos
authors.initials: C
authors.lastname: Vay
authors.forename: Ana
authors.initials: A
authors.lastname: Di Martino
authors.forename: Sara
authors.initials: S
authors.lastname: Kaufman
authors.forename: Daniela
authors.initials: D
authors.lastname: Centrón
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001118:Argentina / Q000453:epidemiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D000077731:Meropenem; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013845:Thienamycins / Q000494:pharmacology; D001618:beta-Lactamases / Q000032:analysis / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D013845:Thienamycins; D015378:Imipenem; C466679:beta-lactamase OXA-23; D001618:beta-Lactamases; C534889:beta-lactamase OXA-58, Acinetobacter baumannii; D000077731:Meropenem