en Anti-microbial agents, resistance and treatment protocols Anti-microbial agents, resistance and treatment protocols Original article Original article <span style="font-size:11pt"><span style="line-height:normal"><span sans-serif="" style="font-family:Calibri,"><b><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Introduction: </span></span></b><i><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Pseudomonas aeruginosa, </span></span></i><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">a nosocomial pathogen, causes respiratory infections, particularly in individuals with cystic fibrosis (CF); it poses a significant challenge due to escalating antibiotic resistance. Phage therapy is emerging as a potential alternative approach to treating antibiotic-resistant bacteria. This study aimed to isolate and identify a highly efficacious bacteriophage targeting</span></span><i><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""> P. aeruginosa</span></span></i><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">.<b> Methods: </b><span style="color:black">Sewage samples from Mofid Children&#39;s Hospital were collected and titrated using a double-layer plaque assay. After plaque detection, the phage was isolated, and then the host range, adsorption </span>rate, and stability were evaluated through spot tests and double-layer plaque assays. Phage morphology was determined using transmission electron microscopy (TEM).<b> Results: </b>Of the three sewage samples collected, one contained phage. We isolated a lytic bacteriophage that exhibited clear plaque formation and induced lysis in planktonic <i>P. aeruginosa</i>. TEM analysis revealed that the phage belonged to the <i>Myoviridae</i> family. The phage had a broad host range and demonstrated optimal stability at 37 &deg;C and pH 7<span style="background:white">. </span><b>Conclusion: </b>The isolated phage can potentially be used for treating <i>P. aeruginosa</i> lung infections, offering an alternative approach to address drug-resistant isolates.</span></span></span></span></span><br> &nbsp; Bacteriophage, Cystic fibrosis, Myoviridae, Phage therapy, Pseudomonas aeruginosa, Antibiotic resistance 136 140 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-496-1&slc_lang=en&sid=1 Mahshid Setayesh Nia setayeshnia.mahshid@gmail.com 0009-0009-5677-1908 No Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Ameneh Elikaei a.elikaei@alzahra.ac.ir 0000-0002-6731-5977 Yes Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Ahya Abdi Ali abdialya@yahoo.com 0000-0003-2425-9503 No Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran Zeynab Rezaei zeinabrezaee76@gmail.com 0000-0003-2273-8965 No Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran