title: Characterization of AmpC, CTX-M and MBLs types of β-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli producing Extended Spectrum β-lactamases in Kerman, Iran.
abstract: BACKGROUND
  Extended spectrum β-lactamases (ESBLs) and AmpC β-lactamases enzyme are major sources of resistance to β-lactam antibiotics especially in Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae. Increasing frequency of the co-existence of ESBLs with AmpC-β-lactamases in bacteria is a serious threat for treating bacterial infections.
  
  
  OBJECTIVE
  The aim of this study was to determine the presence of AmpC and CTX-M types of β-lactamases in clinical isolates of E. coli and K. pneumoniae producing ESBLs.
  
  
  METHODS
  Resistance to different antibiotics was determined using the standard disk diffusion method. ESBLs, MBLs and AmpC-β-lactamases were detected by the combination double disk test (CDDT) method and polymerase chain reaction (PCR) was used to determine bla CTX -M genes in the ESBLs and AmpC positive isolates.
  
  
  RESULTS
  The prevalence of ESBLs and AmpC-β-lactamase producer isolates was 181 (43.8%) and 133 (37.2%), respectively. The prevalence of bla CTX -M among isolates was 61 (14.7%).
  
  
  CONCLUSIONS
  Outbreak of isolates co-expressing AmpC-β-lactamases and ESBLs can cause serious problems in the future, regarding the treatment of infections caused by these common enteric pathogens.
authors.affiliation: Department of Microbiology, School of Medicine, Kerman University of Medical Sciences, Kerman, IR Iran.
authors.forename: Shahla
authors.initials: S
authors.lastname: Mansouri
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, IR Iran.
authors.forename: Davood
authors.initials: D
authors.lastname: Kalantar Neyestanaki
authors.affiliation: Physiology Research Center, Kerman University of Medical Sciences, Kerman, IR Iran.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Shokoohi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, IR Iran.
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Halimi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, IR Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Beigverdi
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences. Tehran, IR Iran.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Rezagholezadeh
authors.affiliation: Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences. Tehran, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Hashemi
keywords: AmpC-β-lactamases; Antibiotic Resistance; ESBLs; Escherichia coli; Klebsiella pneumoniae; blaCTX-M