en مقاومت پادزیستی (آنتی بیوتیکی) Antibiotic Resistance مقاله پژوهشی Original Research Article <p style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><b><span style="background:#1f497d"><span style="color:white"><span style="letter-spacing:-.1pt">Background and Aim:</span></span></span></b><span lang="EN-ID">&nbsp;<em>Pseudomonas (P.) aeruginosa</em> is a Gram-negative bacterium that causes lung infection in cystic fibrosis (CF) patients by forming biofilms, which contribute to antibiotic resistance. The genetic diversity among strains could be important epidemiologically in the community of CF patients. This study investigated <em>P. aeruginosa </em>strains from CF patients&rsquo; sputum, focusing on their antibiotic resistance, biofilm production, and genetic diversity to understand their epidemiological relations.</span><br> <b><span style="background:#1f497d"><span style="color:white"><span style="letter-spacing:-.1pt">Materials and Methods:</span></span></span></b> <span lang="EN-ID">Sixty-five samples of <em>P. aeruginosa</em> were isolated from CF patients with pulmonary infection symptoms (October 2023 to October 2024) admitted to Imam Khomeini Children&#39;s Hospital in Tehran. The antibiotic susceptibility patterns of these strains were examined using disk diffusion method (Kirby-Bauer), based on the CLSI standard. Moreover, to evaluate colistin susceptibility, broth microdilution (BMD) method was used. The strains&#39; ability to produce biofilms was evaluated using a microtiter plate (MTP) assay. Finally, RAPD-PCR (Random Amplified Polymorphic DNA- Polymerase Chain Reaction) was employed for genetic analysis, using the short primer 272.</span><span style="color:black"> </span><br> <b><span style="background:#1f497d"><span style="color:white"><span style="letter-spacing:-.1pt">Results:</span></span></span></b> <span lang="EN-ID">About 61.53% of <em>P. aeruginosa</em> strains exhibited multidrug resistance (MDR), while 30.7% of the strains exhibited extensively drug resistance (XDR) characteristics. The highest levels of antibiotic resistance were found against amoxicillin, amikacin, and cefepime. XDR and MDR strains exhibited strong biofilm-forming ability. The 65 studied strains were classified into 19 groups based on RAPD-PCR patterns, with six strains sharing similar genetic traits divided into four categories.</span><br> <b><span style="background:#1f497d"><span style="color:white"><span style="letter-spacing:-.1pt">Conclusion:</span></span></span></b>&nbsp;The study showed elevation in antibiotic resistance in <em>P. aeruginosa </em>and established a strong connection between biofilm production and resistance. Some isolates exhibited similar genetic patterns, indicating possible cross-infection.</span></span></p> Biofilm, Cystic Fibrosis, Multidrug Resistance, RAPD-PCR, Pseudomonas aeruginosa 191 202 http://ijmm.ir/browse.php?a_code=A-10-2779-1&slc_lang=en&sid=1 Azadeh Ehsani azeh9061@gmail.com 100319475328460032391 0009-0003-5535-9061 Yes Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran Neda Soleimani n-soleimani@sbu.ac.ir 100319475328460032392 100319475328460032392 No Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran Mohammadreza Modaresi Estehbanati modaresipul@gmail.com 100319475328460032393 100319475328460032393 No Department of Pediatric Pulmonary and Sleep Medicine, Children Medical Center, Tehran University of Medical Sciences, Tehran, Iran