Isolation and Identification of a Sewage Pseudomonas aeruginosa-infecting Bacteriophage

Introduction: Pseudomonas aeruginosa, 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 P. aeruginosa. Methods: Sewage samples from Mofid Children’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 rate, and stability were evaluated through spot tests and double-layer plaque assays. Phage morphology was determined using transmission electron microscopy (TEM). Results: Of the three sewage samples collected, one contained phage. We isolated a lytic bacteriophage that exhibited clear plaque formation and induced lysis in planktonic P. aeruginosa. TEM analysis revealed that the phage belonged to the Myoviridae family. The phage had a broad host range and demonstrated optimal stability at 37 °C and pH 7. Conclusion: The isolated phage can potentially be used for treating P. aeruginosa lung infections, offering an alternative approach to address drug-resistant isolates.