title: Prevalence of CTX-M-Type and PER Extended-Spectrum β-Lactamases Among Klebsiella spp. Isolated From Clinical Specimens in the Teaching Hospital of Kashan, Iran.
abstract: BACKGROUND
  Extended-spectrum β-lactamases (ESBLs) is one of the most important mechanisms of resistance to β-lactams especially among Enterobacteriaceae family including Klebsiella spp. Different types of extended-spectrum β-lactamases including CTX-M-type and PER enzymes are identified among gram negative bacteria.
  
  
  OBJECTIVE
  The current study aimed to determine the prevalence of CTX-M-type and PER extended-spectrum β-lactamases among Klebsiella spp. isolated from clinical specimens in the teaching hospital of Kashan, Iran.
  
  
  METHODS
  One hundred Klebsiella spp. were isolated from clinical specimens of hospitalized patients at Shahid-Beheshti hospital from December 2012 to November 2013. Disk diffusion method was used to determine the susceptibility of these isolates to 14 different antimicrobial agents; disks were purchased from MAST company (United Kingdom). The phenotypic double disk synergy confirmatory test was used to screen the isolates to produce extended-spectrum β-lactamase. DNAs of isolates were extracted using boiling method and PCR assay was used to characterize the bla CTX-M type and bla PER genes. The purified PCR products were sent to Macrogen research company (Korea) for sequencing.
  
  
  RESULTS
  Of the total 100 Klebsiella isolates, %93 was susceptible to imipenem. Resistance to ampicillin, ceftazidime, ceftriaxone, aztreonam and cefotaxime was (92%), (67%), (65%), (64%) and (59%), respectively. The phenotypic confirmatory test (PCT) confirmed that 35% (n = 35) of the isolates were ESBL-producing Klebsiella strains. The prevalence of bla CTX-M type and bla RER genes among Klebsiella isolates were 28% (n = 28) and 9% (n = 9), respectively.
  
  
  CONCLUSIONS
  The prevalence of ESBL-producing Klebsiella strains in Shahid-Beheshti hospital in Kashan has increased. The study concluded that there was a high prevalence of the bla CTX-M type gene among ESBL positive isolates.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, Kashan University of Medical Sciences, Kashan, IR Iran.
authors.forename: Atena
authors.initials: A
authors.lastname: Amiri
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, Kashan University of Medical Sciences, Kashan, IR Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Firoozeh
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, Kashan University of Medical Sciences, Kashan, IR Iran.
authors.forename: Rezvan
authors.initials: R
authors.lastname: Moniri
authors.affiliation: Department of Parasitology and Mycology, School of Medicine, Alborz University of Medical Sciences, Karaj, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zibaei
keywords: Clinical Specimens; ESBL; blaCTX-M