title: Effect of drug treatment options on the mobility and expression of blaKPC.
abstract: OBJECTIVE
  Both transposition and increases in gene expression have been implicated in the success of KPC-producing pathogens, but the stimulus required for these phenomena are unknown. It is possible that exposure to antimicrobials during patient treatment increases bla(KPC) expression or induces Tn4401 transposition. The purpose of this study was to determine if exposure to carbapenems or other antimicrobial drug classes could stimulate expression of bla(KPC) or the in vitro transposition of Tn4401.
  
  
  METHODS
  Five KPC-producing clinical isolates were evaluated in this study. Gene expression of RNA from each isolate exposed to subinhibitory, MIC or suprainhibitory levels of antibiotics was evaluated using real-time RT-PCR. Southern blots were performed on plasmids from isolates exposed to subinhibitory levels of antibiotics.
  
  
  RESULTS
  There were subtle changes in bla(KPC) RNA expression following antibiotic exposure that were both strain and drug dependent. Multiple plasmids ranging from ~8 to >200 kb were observed for the Enterobacteriaceae isolates, whereas the Pseudomonas aeruginosa isolate had one ~55 kb plasmid. No changes in hybridization patterns or binding intensity for the bla(KPC) probe were observed after antibiotic exposure.
  
  
  CONCLUSIONS
  While the changes in bla(KPC) RNA expression are subtle, the different responses observed suggest both strain- and genera-specific variations in response to different antibiotic treatments.
authors.affiliation: Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Roth
authors.forename: Philip D
authors.initials: PD
authors.lastname: Lister
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Hanson
mesh_terms: D015139:Blotting, Southern; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects*; D022761:Gene Transfer, Horizontal / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000032:analysis; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D001618:beta-Lactamases
keywords: KPC; Tn4401; collateral damage