en Epidemiology Original Article <div style="text-align: justify;"><span style="font-family:arial;"><strong>Background</strong>: In recent years, the risk of acquiring antibiotic resistance has been increasing due to the widespread use of antibiotics. This study aims to evaluate the antibiotic resistance pattern in patients referred to Ali-ebn Abi-Taleb hospital.<br> <strong>Materials and Methods:</strong> In a descriptive study, samples of urine, blood, cerebrospinal fluid, and body fluid were collected from patients referred to Ali-ebn Abi-Taleb Hospital from September 2014 to February 2015. Of these, 687 isolates identified as <em>E. coli</em> were tested for antibiotic susceptibility against 15 antibiotics by the Kirby- Bauer method based on CLSI 2015. The relevant prevalence, percentage, and mean were reported using SPSS (version 16).<br> <strong>Results:</strong> A total of 10824 samples were collected. A total of 866 isolates were grown on an agar medium, and 80.3% of the samples were isolated from women. The highest rate of antibiotic resistance was reported to be for Amoxicillin (82.2%). The lowestrate of antibiotic resistance was reported against Nitrofurantoin (14%).<br> <strong>Conclusions: </strong>We concluded there is an increasing rate of antibiotic resistance among <em>E. coli</em> isolates. Therefore, the necessity of identifying drug resistance is apparent using precise and straightforward methods to prevent the extensive distribution of antibiotic resistantagents.</span><br> &nbsp;</div> Antibiotic Resistance,E. coli,Drug Resistance, 118 122 http://johe.rums.ac.ir/browse.php?a_code=A-10-330-1&slc_lang=en&sid=1 Maryam Meskini meskini155@gmail.com 22400319475328460010920 22400319475328460010920 No PhD Student, Department of Microbiology and Microbiology Research Center, Pasteur Institute, Tehran, Iran; Student Research Committee, Pasteur Institute of Iran, Tehran, Iran. Pasteur Institute Sohrab Farhadi 22400319475328460010921 22400319475328460010921 No BSc Student, Department of Microbiology and Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Baqiyatallah University of Medical Sciences Davoud Esmaeili esm114@gmail.com 22400319475328460010922 22400319475328460010922 Yes Associate Prof., Department of Microbiology and Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran; Applied Virology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Baqiyatallah University of Medical Sciences