en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <strong>Introduction: </strong>Integronsare are mobile genetic elements which play an essential role in the distribution of antibiotic-resistant genes among bacteria. This study aimed to investigate the Class I integron in <em>Klebsiella pneumoniae</em> clinical isolates and its association with multiple drug resistance (MDR). <strong>Methods</strong>: We obtained 30 <em>K. pneumoniae</em> isolates from patients admitted to the ICU at Shahid Beheshti Hospital in Babol City, Mazandaran province, Iran. Different classes of antimicrobials were used to determine the resistance pattern. A polymerase chain reaction (PCR) was performed to detect the <em>int1 </em>gene of the class I integrons. We also investigated the suitability of the two pairs of primers for the detection of the <em>intl</em> gene. <strong>Results</strong>: Antibiotic susceptibility testing revealed 90% resistance to ceftizoxime, cefotaxime, and cefepime, 88.6% to cefazolin, gentamicin, ticarcillin, and ceftriaxone, 83.3% to imipenem, 60% to ciprofloxacin, 56.6% to ofloxacin, and 36.6% to amikacin. The PCRs with two pairs of primers, one designed previously and the other in this study, detected <em>int1</em> in 36.6% and 60% of samples, respectively. <strong>Conclusion: </strong>The <em>int1 </em>gene was of high prevalence (60%) in <em>K. pneumoniae</em> isolates. This factor could play a significant role in the spread of MDR strains. Also, failure to adhere to essential points in the design of the primer can lead to the production of primers with low specificity and efficiency, which reduces the proper identification of antibiotic resistance genes. Klebsiella pneumonia, Integron, Anti-Bacterial Agents 24 28 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-228-1&slc_lang=en&sid=1 Parisa Sabbagh maali.amirhosein@gmail.com 0000-0002-3570-9795 No Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Azadeh Ferdosi-Shahandashti amir9226012@gmail.com 0000-0003-2570-1420 No Department of Microbiology, School of Sciences, Islamic Azad University, Ayatollah Amoli Branch, Amol, Iran Mehdi Rajabnia neginmaali79@gamil.com 0000-0002-5343-0878 No Department of Microbiology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran Amirhosein Maali 0000-0002-0699-3010 No Pasteur Institute of Iran, Tehran, Iran Elaheh Ferdosi Shahandashti elaheh.ferdosi@yahoo.com 000000023678683X Yes Department of Medical Biotechnology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran