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

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 blactx-m type gene among esbl positive isolates. patients and 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 blactx-m type and blaper genes. the purified pcr products were sent to macrogen research company (korea) for sequencing. 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. 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 blactx-m type and blarer genes among klebsiella isolates were 28% (n = 28) and 9% (n = 9), respectively. objectives 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.