en Medical Biology Medical Biology مقاله پژوهشی Original Research Article <p style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><strong new="" roman="" style="font-family: " times=""><span style="color:#ffffff;"><span style="background-color:#16a085;">Background and Objective:</span></span>&nbsp;</strong><span style="line-height:150%"><span style="line-height:150%">Burn wound infections caused by <i>Pseudomonas aeruginosa</i> exhibiting &beta;-lactam antibiotic resistance are one of the greatest challenges of antimicrobial treatment. In this context, <i>P. aeruginosa</i> strains harboring resistance mechanisms, such as production of extended-spectrum beta-lactamases have the highest clinical impact no the management of burn wound infections. The aim of this study was to investigate the antibacterial activity of iron oxide nanoparticles (IONPs) against <i>P. aeruginosa</i> harboring Cefotaximase-Munich (<i>CTX-M</i>) gene strains.</span></span><br> <strong new="" roman="" style="font-family: " times=""><span style="color:#ffffff;"><span style="background-color:#16a085;">Materials and Methods:</span></span>&nbsp;</strong><span style="line-height:150%"><span style="line-height:150%">In this study, 60 isolates of <i>P. aeruginosa</i> were collected from burn wound infections referred to major hospitals of Tehran, Iran. All strains were assessed for the presence of beta-lactamase <i>CTX-M</i> gene by polymerase chain reaction. In- vitro antibacterial effect of IONPs against <i>P. aeruginosa</i> harboring <i>CTX-M</i> strains was assessed by microdilution assay and <i>CTX-M</i> gene expression profile using Real-time PCR.</span></span><br> <strong new="" roman="" style="font-family: " times=""><span style="color:#ffffff;"><span style="background-color:#16a085;">Results:</span></span></strong>&nbsp;<span style="line-height:150%"><span style="line-height:150%">Our results demonstrated that 12/60 isolates were identified to be <i>CTX-M</i>-producing <i>P. aeruginosa</i> with multidrug resistance phenotypes. Our results indicated that the CTX-M gene frequency was 20%. We found that the expression of <i>CTX-M</i> gene in <i>P. aeruginosa</i> strains treated with IONPs (6.21&plusmn;4.1) was much lower than that of non-treated (9.73&plusmn;2.02) nanoparticles (<i>P</i>=0.000). Also, IONPs at 256 &mu;g/ml had inhibitory effect on the growth of <i>P. aeruginosa</i> by suppressing <i>CTX-M</i> expression.</span></span><br> <strong new="" roman="" style="font-family: " times=""><span style="color:#ffffff;"><span style="background-color:#16a085;">Conclusion:</span></span>&nbsp;</strong><span style="line-height:150%"><span style="line-height:150%">IONPs have potent antibacterial properties against <i>P. aeruginosa</i> through the suppression of <i>CTX-M </i>expression. According to our results, IONPs are promising tools for the development of new antimicrobial drugs against <i>P. aeruginosa</i>, since these composites have potential to decrease antibiotic resistance.</span></span></span></span></p> Iron oxide nanoparticles, Pseudomonas aeruginosa, ESBL, CTX, Real-Time-PCR 289 294 http://journal.zums.ac.ir/browse.php?a_code=A-10-5714-1&slc_lang=en&sid=1 Fatemeh Piri fatemeh.piri62@gmail.com 5200319475328460073517 5200319475328460073517 No Dept. of Anesthesia, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran Kumarss Amini dr_kumarss_amini@yahoo.com 5200319475328460073518 5200319475328460073518 Yes Dept. of Microbiology, Saveh Branch, Islamic Azad University, Saveh, Iran Minoo Mohammadi minoo.mohamadi15@yahoo.com 5200319475328460073519 5200319475328460073519 No Dept. of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran