en Clinical Medicine Clinical Medicine مقاله پژوهشی Original Research Article <div style="text-align: justify;"><span style="font-family:Times New Roman;"><span style="font-size:11pt"><span style="line-height:150%"><b><span style="font-size:12.0pt"><span style="line-height:150%">Background & Objective:</span></span></b><span style="font-size:12.0pt"><span style="line-height:150%"> Enterobacteriaceae, a family of Gram-negative bacteria in the normal gut flora, are common human pathogens. The rising fecal carriage of carbapenemase-producing (CPE) and extended-spectrum &beta;-lactamase-producing Enterobacteriaceae (ESBL-PE) poses significant resistance to beta-lactam antibiotics. Due to this issue, This study focused on the prevalence and molecular characterization of beta-lactamase genes (<i>blaKPC, blaIMP, blaVIM, blaNDM, blaSHV, blaTEM, blaOXA, and blaCTX-M</i>) in Enterobacteriaceae isolates from hospitalized patients in Shahriar, Iran.<b> </b></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:150%"><b><span style="font-size:12.0pt"><span style="line-height:150%">Materials & Methods:</span></span></b><span style="font-size:12.0pt"><span style="line-height:150%"> A total of 85 stool samples were collected from hospitalized patients in the ICU and general wards of Imam Sajjad Hospital, Shahriar. Bacterial isolates were identified using standard microbiological methods for identification of Enterobacteriaceae. Antibiotic susceptibility profile of isolates was analysed by using the disc diffusion, and Minimum inhibitory concentrations (MICs) method based on the Clinical and Laboratory Standards Institute (CLSI) 2023 guidelines.&nbsp; Phenotypic detection of ESBL and such as metallo-beta-lactamase (MBL) resistance, was performed using combined disc tests with specific inhibitors. &nbsp;PCR amplification with specific primer was used for detection beta-lactamase genes including <i>bla_KPC, bla_IMP, bla_VIM, bla_NDM</i>,<i> bla_SHV,bla_TEM,bla_OXA</i> and <i>bla_CTX-M.</i><b> </b></span></span></span></span><br> <span style="font-size:11pt"><span style="line-height:150%"><b><span style="font-size:12.0pt"><span style="line-height:150%">Results:</span></span></b><span style="font-size:12.0pt"><span style="line-height:150%"> From 85 samples, 19 isolates of <i>Klebsiella pneumoniae</i> (20.43%) and 66 isolates of <i>Escherichia coli</i> (79.57%) were identified. Among these, 31 isolates exhibited </span></span><span style="font-size:12.0pt"><span style="line-height:150%">ESBL and</span></span> <span style="font-size:12.0pt"><span style="line-height:150%">10 were identified as MBL. Among the 31 carbapenem-resistant or intermediate isolates, all carried the <i>blaCTX-M</i> gene. Additionally, 2 isolates carried the <i>blaNDM-1</i> gene, and another 2 harbored the <i>blaIMP</i> gene. However, the <i>blaKPC</i> and <i>blaVIM</i> genes were not detected in any of the isolates.<br> <b>Conclusion: </b><i>bla_CTX-M </i>gene is one of the most common resistant genes in Iran. According to studies, the prevalence of antibiotic resistance in Iran is rising dramatically, which reduces the choice of antibiotics to treat severe infections in the future.</span></span></span></span></span><br> &nbsp;</div> Fecal Carriage, ESBL, Carbapenem Resistance, Escherichia coli, Klebsiella pneumonia 1 1 http://journal.zums.ac.ir/browse.php?a_code=A-10-7214-1&slc_lang=en&sid=1 Amir Hossein Omidi amirhossein_omidi@yahoo.com 5200319475328460088321 5200319475328460088321 No Department of Epidemiology and Biostatics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran Reyhaneh Seydmohammadi reyhanehseydmohammadi@yahoo.com 5200319475328460088322 5200319475328460088322 No Department of Biochemistry and Biophysics, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Mohammad Reza Mohammadi mreza_mohammadi@modares.ac.ir 5200319475328460088323 5200319475328460088323 No Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Mina Latifian latifianmina1376@gmail.com 5200319475328460088324 5200319475328460088324 No Department of Epidemiology and Biostatics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran Vajihe Sadat Nikbin vsnikbin@yahoo.com 5200319475328460088325 5200319475328460088325 No Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran Fereshteh Atabi feratabi.2nd.1400@gmail.com 5200319475328460088326 5200319475328460088326 No Department of Biochemistry and Biophysics, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Reza Hosseini Doust rhdoust@gmail.com 5200319475328460088327 5200319475328460088327 No Department of Microbiology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Fereshteh Shahcheraghi shahcheraghifereshteh@yahoo.com 5200319475328460088328 5200319475328460088328 Yes Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran