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

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. 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. 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 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.