title: Multi-drug resistance profiles and the genetic features of Acinetobacter baumannii isolates from Bolivia.
abstract: BACKGROUND
  Acinetobacter baumannii is opportunistic in debilitated hospitalised patients. Because information from some South American countries was previously lacking, this study examined the emergence of multi-resistant A. baumannii in three hospitals in Cochabamba, Bolivia, from 2008 to 2009.
  
  
  METHODS
  Multiplex PCR was used to identify the main resistance genes in 15 multi-resistant A. baumannii isolates. RT-PCR was used to measure gene expression. The genetic environment of these genes was also analysed by PCR amplification and sequencing. Minimum inhibitory concentrations were determined for key antibiotics and some were determined in the presence of an efflux pump inhibitor, 1-(1-napthylmethyl) piperazine.
  
  
  RESULTS
  Fourteen strains were found to be multi-resistant. Each strain was found to have the blaOXA-58 gene with the ISAba3-like element upstream, responsible for over-expression of the latter and subsequent carbapenem resistance. Similarly, ISAba1, upstream of the blaADC gene caused over-expression of the latter and cephalosporin resistance; mutations in the gyrA(Ser83 to Leu) and parC (Ser-80 to Phe) genes were commensurate with fluoroquinolone resistance. In addition, the adeA, adeB efflux genes were over-expressed. All 15 isolates were positive for at least two aminoglycoside resistance genes.
  
  
  CONCLUSIONS
  This is one of the first reports analyzing the multi-drug resistance profile of A. baumannii strains isolated in Bolivia and shows that the over-expression of theblaOXA-58, blaADC and efflux genes together with aminoglycoside modifying enzymes and mutations in DNA topoisomerases are responsible for the multi-resistance of the bacteria and the subsequent difficulty in treating infections caused by them.
authors.affiliation: The University of Edinburgh, Edinburgh, United Kingdom. brunoldlopez@yahoo.co.in
authors.forename: Bruno Silvester
authors.initials: BS
authors.lastname: Lopes
authors.forename: Lucia
authors.initials: L
authors.lastname: Gallego
authors.forename: Sebastian Giles Becket
authors.initials: SG
authors.lastname: Amyes
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001838:Bolivia; D027081:DNA Gyrase / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010879:Piperazines / Q000494:pharmacology; D018272:Porins / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
chemical_list: C492436:AdeA protein, Acinetobacter baumannii; D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C561703:CarO protein, Acinetobacter baumannii; D026901:Membrane Transport Proteins; D010879:Piperazines; D018272:Porins; C048241:1-(1-naphthyl)piperazine; D001618:beta-Lactamases; D027081:DNA Gyrase