en Medical Biology Medical Biology مقاله پژوهشی Original Research Article <p style="text-align: justify;"><span style="font-family:times new roman;"><span style="font-size:14px;"><span style="color:#008080;"><strong>Background & Objective:</strong></span> The production of plasmid-mediated AmpC beta-lactamases (PMABLs) among urinary <em>Klebsiella pneumoniae</em> isolates causes a severe problem to the successful treatment of urinary tract infections (UTIs). This study was designed to evaluate antimicrobial resistance, the presence of AmpC beta-lactamase genes, and the genetic relatedness among <em>K. pneumoniae</em> strains separated from patients with UTI.<br> <span style="color:#008080;"><strong>Materials & Methods:</strong></span> In this cross-sectional descriptive study, a total of 100<em> K. pneumoniae </em>isolates were collected from UTI cases in Milad Hospital, Tehran, Iran. The sensitivity of the isolates to 12 antibiotics was tested using the Kirby-Bauer disk diffusion method. AmpC production was determined using a boronic acid combined-disk test. Polymerase chain reaction (PCR) was carried out to screen all isolates with family-specific <em>PMABL</em> genes. The genetic relatedness of AmpC-producing isolates was determined by an enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR).<br> <span style="color:#008080;"><strong>Results: </strong></span>Over a period of 11 months, PMABLs were detected in 49 isolates (49%) of <em>K. pneumoniae</em>. Resistance to at least three classes of antimicrobials was detected in 30 (61.2%) PMABL producers. Among AmpC producers, 34 isolates harbored only one <em>AmpC </em>gene group, including MOX (n=11), EBC (n=8), ACC (n=7), CIT (n=4), FOX (n=2), and DHA (n=2). Multiple <em>AmpC </em>gene groups were detected in 15 isolates. The ERIC-PCR showed the polyclonal distribution of AmpC-producing isolates.<br> <span style="color:#008080;"><strong>Conclusion:</strong></span> In our study, a high frequency of AmpC-producing <em>K. pneumoniae</em> was observed. This is the first report of ACC type AmpC beta-lactamase in Iran. Strategies to minimize the spread of AmpC beta-lactamase-producing isolates should be implemented.</span></span></p> Klebsiella pneumoniae, AmpC beta-lactamases, Urinary tract infections 23 30 http://journal.zums.ac.ir/browse.php?a_code=A-10-5009-1&slc_lang=en&sid=1 Maryam Ghane مریم قانع ghane@iiau.ac.ir 5200319475328460048324 5200319475328460048324 Yes Dept. of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran Laleh Babaeekhou لاله بابایی‌خو babaeekhou@iiau.ac.ir 5200319475328460048325 5200319475328460048325 No Dept. of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran Mahdi Jafar Shanjani مهدی جعفرشنجانی mehdi.jafari.shanjani@gmail.com 5200319475328460048326 5200319475328460048326 No Dept. of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran