Baqiyatallah University of Medical Sciences Hospital Practices and Research 2476-390X 10 3 2025 09 20 Assessment of the Frequency of qnrS and qnrA Genes in Clinical Isolates of Klebsiella pneumoniae and Their Relationship with Antibiotic Resistance Patterns and Iron Oxide Nanoparticles 699 704 230312 10.30491/hpr.2025.485003.1457 EN Zahra Malekzadeh Department of Biology, Bon.C., Islamic Azad University, Bonab, Iran Zahra Hojjati Bonab Department of Microbiology, Bon.C., Islamic Azad University, Bonab, Iran 0000-0002-6164-2416 Hossein Soltanzadeh Department of Biology, Bon.C., Islamic Azad University, Bonab, Iran Journal Article 2024 11 16 <strong>Background:</strong> <em>Klebsiella pneumoniae</em> is a gram-negative, short, facultative anaerobic bacillus that commonly grows in laboratory culture environments, including blood agar, EMB, Mueller-Hinton agar, and nutrient agar. As an opportunistic pathogen, it poses significant treatment challenges due to increasing antibiotic resistance. <strong>Objectives:</strong> The purpose of this study is to determine the relationship between antibiotic resistance and the frequency of <em>qnrS</em> and <em>qnrA</em> genes in clinical isolates of <em>Klebsiella pneumonia</em>. <strong>Methods: </strong>In this study, 100 patients referred to Sina Hospital in Tabriz due to urinary tract infections (UTIs) were examined. Common biochemical tests confirmed the presence of Klebsiella in 20 samples. The antibiotic sensitivity pattern of the isolates was determined using the disc diffusion method, and the results of the antibiogram test were analyzed. The resistance of the samples to five different types of antibiotics was assessed. <strong>Results:</strong> In this study, the highest antibiotic resistance was observed against nalidixic acid. The presence of the <em>qnrS</em> gene was confirmed in five isolates of <em>Klebsiella pneumoniae</em>, while the <em>qnrA</em> gene was absent in all isolates. The sensitivity of the <em>Klebsiella pneumoniae</em> strain to iron oxide nanoparticles was evaluated using the well method at a concentration of 0.08 g in 100 ml of water. One sample in a volume of 100 ml and two samples in a volume of 200 ml formed halos with diameters of 11 mm, 14 mm, and 12 mm, respectively. <strong>Conclusion: </strong>The findings of the present study showed that the frequency of <em>qnrS</em> genes was high in fluoroquinolone-resistant samples of <em>Klebsiella pneumoniae</em>, and this factor could lead to progressive antimicrobial resistance in different hospital departments. https://www.jhpr.ir/article_230312_ff4e198642cd7270570d21ff3c798850.pdf