Zahra Kohanrooz Bijarpas - Department of Biology, Islamic Azad University- Parand Branch, Tehran, Iran.
Saeed Zaker Bostanabad - Microbiology Department, Islamic Azad University-Parand Branch, Tehran, Iran
Farzaneh Tafvizi - Department of Biology, Islamic Azad University- Parand Branch, Tehran, Iran

Background and Aim:: Extended-spectrum beta-lactamaseS of SHV,PER and VEB type is considered as an Important mechanism resistant to beta-lactamases in gram- negative pathogen and is widely increasing. Klebsiella pneumonia species are able to produce extended-spectrum beta- lactamase (ESBLs).Methods:In this analytical- descriptive study antibacterial susceptibility patterns of 176 Klebsiella pneumonia has been tested to Cefepime, Ampicillin, Gentamicin, Cefalotine, Ceftazidime, Ciprofloxacin, Imipenem, Cefotaxime , Nitrofurantoin using disk diffusion method. The presence of SHV,PER and VEB genes were assessed by using PCR MethodResults:Confirmatory phenotypic test showed 56/81% of the isolates were ESBL positive. The prevalence of SHV,PER and VEB genes in isolated Klebsiella pneumonia was 34%,%13 and %17 respectively. In this study, the highest resistance was observed for ampicillin antibiotics (%89) and the least resistance to antibiotic imipenem (%7).Conclusion:High frequency of SHV,PER and VEB genes in ESBL produsing isolates indicates that this enzyms plays an important role in resistance to beta lactam containing anti biotics. Therefore, proper infection control tools and appropriate therapeutic approaches in different parts of the hospitals are necessary to prevent their release

Klebsiella pneumonia ,ESBL , bla SHV,PER , VEB,PCR