Background & aim: Resistance to Extended Spectrum Beta-Lactamase (ESBL) is one of the most widespread enzymatic beta-lactamase in those bacteria which cause infections in hospitals. One major reason for this type of resistance seems to be the arbitrary and/or excessive use of antibiotics. At present, there is no resistance pattern for bacterial strains which cause infections in hospitals with ESBL mechanism in different regions of Iran, they spread differently in different seasons, and more and more cases of the resistance are being reported. Hence, the present study aimed to determine the antibiotic resistance patterns and bacterial strains and to investigate the presence of Beta-lactamase SHV, TEM , CTX-M genes in those Klebsiella strains which produce ESBL. The clinical samples of the study were collected from Yahyanejad Hospital in Babol. 

Methods: The present descriptive-analytical study was carried out in six-months in 2014, and  2075 clinical samples( of blood, urine, respiratory discharge, throat culture, wound culture, pleural fluid culture, CSF, Ascitic fluid culture, Synovial culture, and bone marrow smear) were gathered. 39 Klebsiella strains were identified among the hospitalized and out-patients of Yahyanejad Hospital using disk diffusion method and CLSI instructions. Antibiotic allergy tests were given for all the strains, and all the strains were separated using synergic double discs to check the presence of ESBL. In the next phase of the study, the extracted DNA were examined in terms of the presence of SHV, TEM , CTX-M by using specific primers and employing PCR method. The collected data were analyzed using, SPSS and K² tests.

Results: The frequencies of the identified strains were: isolated Klebsiella Pneumonia: 31(79.49%), isolated Klebsiella Oxytoca: 5(12.82%), and isolated Klebsiella Ozaenae: 3(7.69%). Among  the isolated Klebsiella stains  19(48.72%) were resistant to cefotaxime , 14(35.90%) to ceftazidime, 18(46.16%) to Amikacin, 13(33.34%) to Meropenem, 18(46.15%) to Ciprofloxacin, 26(66.67%) to Ceftriaxone, 12(30.77%) to Piperacillin Tazobactam, and 16(41.03%) to Ampicilin sulbactam. Also, among the 39 isolated Klebsiella Pneumonia, there were 10(25.64%) isolated positive ESBL,  all the 10(100%) isolated strains  having Beta-Lactamase SHV gene, there were 6(60%) isolated positive TEM gene and there were 4(40%) isolated positive CTX-M gene.

Conclusion: Considering the high rate of resistance to third generation cephalosporin, it is imperative to perform accurate antibiogram and avoid irrational prescription of antibiotics in treating infections due to organisms which produce ESBL. In addition, it is of vital importance to screen the clinical samples in terms of resistance to ESBL, and to prepare guidelines for physicians to help realize the disease and to treat the patients properly. Also , the extracted DNA were examined samples purified in identifying genes SHV ,TEM  ,CTX-M in Klebsiella Pneumonia is possible PCR method.