title: [Study on the molecular mechanism of transferable multiple-antibiotic resistance in extended-spectrum beta-lactamase-producing clinical isolates].
abstract: OBJECTIVE
  To investigate the molecular mechanism of transferable multiple-antibiotic resistance in extended-spectrum beta-lactamases (ESBLs) producing isolates.
  
  
  METHODS
  Antibiotics susceptibility was tested by E-test method, and multi-resistance plasmids were screened and isolated by extracting transformant plasmids. Inserted gene Cassettes of class 1 integron were amplified and analyzed by polymerase chain reaction (PCR) and DNA sequencing.
  
  
  RESULTS
  Eight of the nine ESBL-producing plasmids were found to comprise class 1 integron sequence, of them 7 harbored 1 or 2 antibiotic resistant gene cassettes which encoding resistance to aminoglycosides (aacA4, aadA2 or aadA5), trimethoprim (dhfrA12 or dfrA17), rifampicin (arr-3) and chloramphenicol (cmlA6). The function of these gene cassettes corresponded to the resistance profiles of their electro-transformants.
  
  
  CONCLUSIONS
  Multi-resistance gene cassettes located on plasmids and mediated by class 1 integron may play an important role in causing the development and dissemination of multiple-antibiotic resistance in ESBL-producing clinical isolates.
authors.affiliation: Department of Respiratory Medicine, The Third Affiliated Hospital of Sun Yat-sen university, Guangzhou 510630, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Ying-chun
authors.initials: YC
authors.lastname: Tang
authors.forename: Ben-quan
authors.initials: BQ
authors.lastname: Wu
authors.forename: Kou-xing
authors.initials: KX
authors.lastname: Zhang
authors.forename: Tian-tuo
authors.initials: TT
authors.lastname: Zhang
authors.forename: Xiao-gang
authors.initials: XG
authors.lastname: Bi
authors.forename: Jia-xin
authors.initials: JX
authors.lastname: Zhu
authors.forename: Shu-qing
authors.initials: SQ
authors.lastname: Tan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D006090:Gram-Negative Bacteria / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D019426:Integrases / Q000235:genetics; D032023:Integrons; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D019426:Integrases; D001618:beta-Lactamases