title: Prevalence of Class 1 Integrons and Extended Spectrum Beta Lactamases among Multi-Drug Resistant Escherichia coli Isolates from North of Iran.
abstract: BACKGROUND
  Extended spectrum beta lactamases (ESBLs) are an important cause of transferable multidrug resistance (MDR) in gram-negative bacteria. The most described ESBL genes are generally found within integron-like structures as mobile genetic elements. The aim of this study was to identify the accompanying of class 1 integrons and ESBLs in the MDR E. coli isolates.
  
  
  METHODS
  Susceptibility to antimicrobial agents was determined for 33 E. coli strains by the disk diffusion method. Double-disk synergy test was applied for screening ESBL. To identify the strains carrying integrons, the conserved regions of integron-encoded integrase gene intI1 were amplified. For detection of gene cassettes, 5'CS and 3'CS primers were used.
  
  
  RESULTS
  All E. coli isolates were identified as multi-drug resistant. More than 50% of the isolates were resistant to tetracycline, cephalothin, cefuroxime, amoxicillin-clavulanic acid, and third generation cephalosporines. Nearly all of the isolates displayed sensitivity to piperacillin. There was a significant correlation between production of ESBL and resistance to all antibiotics except for ciprofloxacin and piperacillin (P value less than 0.01). Thirty two MDR strains (97%) included class 1 integron, and some isolates that included integrons were similar in the size of gene cassettes. The isolates were different in the resistance profiles; however, some others had similar resistance profiles. Of eight ESBL positive isolates, seven (87.5%) carried class 1 integrons.
  
  
  CONCLUSIONS
  Class 1 integrons were frequent in MDR and also ESBL-producing E. coli isolates. High prevalence of class 1 integrons confirms that integron-mediated antimicrobial gene cassettes are important in E. coli resistance profile.
authors.affiliation: Dept. of Biology, Faculty of Science, University of Guilan, Rasht, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Mehdipour Moghaddam
authors.affiliation: University of Guilan, University Campus 2, Rasht, Iran.
authors.forename: Adeleh Alsadat
authors.initials: AA
authors.lastname: Mirbagheri
authors.affiliation: Dept. of Biology, Faculty of Science, University of Guilan, Rasht, Iran.
authors.forename: Zivar
authors.initials: Z
authors.lastname: Salehi
authors.affiliation: Razi Pathobiology Laboratory, Rasht, Iran.
authors.forename: Seyyed Mahmood
authors.initials: SM
authors.lastname: Habibzade
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D032023:Integrons / Q000235:genetics*; D007492:Iran / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
keywords: Antibiotic; Escherichia coli; Integrons