title: Prevalence of SXT/R391-like integrative and conjugative elements carrying blaCMY-2 in Proteus mirabilis.
abstract: OBJECTIVE
  To characterize the vectors involved in the dissemination of bla(CMY-2) genes in clinical isolates of Proteus mirabilis collected between 1999 and 2007.
  
  
  METHODS
  Plasmid analysis of 19 P. mirabilis carrying ampC genes was performed by PCR-based replicon typing, S1-PFGE and Southern hybridization with ampC and replicon probes. Isolates that could not be characterized were examined for the presence of SXT/R391-like elements. To demonstrate the involvement of these elements in the dissemination of bla(CMY-2), we performed a PCR amplification of the integrase (int) and toxin/antitoxin (TA) genes from SXT/R391-like integrative conjugative elements (ICEs). Later on, I-Ceu-I PFGE gels and hybridization with bla(CMY-2), int and prfC probes were performed. The genetic organization of bla(CMY-2) was also studied.
  
  
  RESULTS
  ampC genes were located on large conjugative plasmids in 11 of the 19 (58%) P. mirabilis studied. However, in eight of these isolates a plasmid was not involved in the mobilization of ampC genes. I-Ceu-I PFGE and hybridization analyses revealed that bla(CMY-2) were chromosomally located in these eight P. mirabilis isolates. The genetic organization of bla(CMY-2) and hybridization analyses revealed that bla(CMY-2) was carried by an ICE almost identical to ICEPmiJpan1 in seven out of these eight isolates.
  
  
  CONCLUSIONS
  The prevalence of ICEs carrying bla(CMY-2) was surprisingly high [37% (7 out of 19)]. This is the first study giving prevalence data on ICEs carrying bla(CMY-2) genes. These results suggest the need to study these mobile genetic elements in the context of dissemination of acquired AmpC β-lactamases and also of other β-lactamases, such as extended-spectrum β-lactamases and carbapenemases.
authors.affiliation: Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Institut d'Investigacions Biomèdiques Sant Pau, Barcelona, Spain.
authors.forename: Caterina
authors.initials: C
authors.lastname: Mata
authors.forename: Ferran
authors.initials: F
authors.lastname: Navarro
authors.forename: Elisenda
authors.initials: E
authors.lastname: Miró
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Walsh
authors.forename: Beatriz
authors.initials: B
authors.lastname: Mirelis
authors.forename: Mark
authors.initials: M
authors.lastname: Toleman
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D006801:Humans; D019426:Integrases / Q000235:genetics; D020071:Interspersed Repetitive Sequences; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D011512:Proteus Infections / Q000188:drug therapy / Q000382:microbiology; D011513:Proteus mirabilis / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D019426:Integrases; C103022:beta-lactamase CMY-2; C048795:AmpC beta-lactamases; D001618:beta-Lactamases