• The survey of antibiotic resistance pattern and prevalence of Tetracycline resistance (tetA, tetB) genes in Escherichia coli isolates collected in Ahar Bagheralolum hospital.
  • Meysam Imanzadeh kaleybar,1,* Mehdi Ghiamirad*,2
    1. M.Sc. student of Microbiology in Mizan Higher Education Institute, Tabriz -Iran
    2. Department of Microbiology, Faculty of Basic Science, Islamic Azad University Ahar Branch, Ahar-Iran


  • Introduction: Escherichia coli is the most important member of normal intestinal flora in humans and animals, and can causing opportunistic infections. Tetracyclines are a family of antibiotics that inhibit pro-tein synthesis by preventing the attachment of aminoacyl-tRNA to the ribosomal acceptor (A) site. They are also used to treat Escherichia coli infections. However, the continued widespread use of antibiotics has led to the development of resistant organisms. This study was conducted to investigate the resistance to tetracyclines and investigate the frequency of tetA and tetB genes among Escherichia coli isolated from patients hospitalized in Ahar hospital.
  • Methods: 120 bacterial samples with initial diagnosis of Gram-negative bacillus (Enterobacteriaceae family) were collected from Ahar Hospital. Samples were processed for microbial and biochemical characterization. Antibiotic susceptibility test was carried out by using disc diffusion method. The distribution of tetracycline resistance (Tcr) genes (tetA and tetB) in isolates were detected by PCR
  • Results: 76 isolates from 120 samples were recognized as E. coli. The higher resistance rate was 82.19% to Ampiciline, and the lowest resistance rate was 8.21% to Gentamycine. 75% and 72.6% of the isolates, however, were resistant to Doxycycline and Tetracycline respectively.The distribution of tetracycline-resistance genes among isolates included tetB 14% , tetA 36%
  • Conclusion: The increase in the resistance of tetracycline with high diversification is an indication of antibiotics overuse. Strict enforcement of regulation is urgently needed to control and prevent the spread of tetracycline resistant strains which are detrimental to the environment.
  • Keywords: Escherichia coli, Antibiotic resistance pattern, tetA, tetB