ABSTRACT

      Background and Objective: Extended-spectrum beta-lactamases (ESBL) are widely produced by Escherichia coli strains. The aim of this study was to determine frequency of bla_OXA-1 and bla_SHV genes in E.coli strains isolated from patients hospitalized in city of Rasht, Iran.

       Methods: In this cross-sectional study, 200 samples were collected from patients. The E. coli strains were identified using morphological characteristics and biochemical tests. Antimicrobial susceptibility testing was performed. The prevalence of the bla_OXA-1 and bla_SHV genes in the E. coli isolated was assessed by PCR method.

       Results: Overall, 160 E. coli strains were isolated. Of these, 83 (51.9%) showed ESBL activity while 71 (48.1%) did not. All positive strains were resistant to cephalothin. Moreover, 98.8% of ESBL-producing strains were resistance to amoxicillin, cefotaxime and ceftriaxone. The prevalence of the bla_OXA-1 and bla_SHV genes in ESBL-producing strains were 45% and 17%, respectively. In addition, 28.9% of the strains had both genes while the genes were absent in 9.6% of the strains.

      Conclusion: Prevalence of the bla_OXA-1gene is higher than that of the bla_{SHV gene}. The absence of both genes in some isolates indicates the possible role of other genes in the ESBL activity.

      Keywords: Prevalence, ESBLs, Escherichia coli, bla_OXA-1gene, bla_SHV gene.