Phage Therapy Potential: Isolation, Characterization, and Host Range of Bacteriophages Active Against MDR Pseudomonas aeruginosa in Abuja, FCT

The re-emergence of bacteriophage therapy as a promising strategy against multidrug-resistant bacterial infections has generated considerable scientific interest, particularly given the dwindling antibiotic pipeline. Nigeria lacks documented bacteriophage resources despite a high burden of MDR infections. This study isolated, characterized, and determined the host range of bacteriophages active against MDR Pseudomonas aeruginosa clinical isolates obtained from the National Hospital Abuja, FCT, North Central Nigeria. Bacteriophages were isolated from hospital sewage, wastewater drains, and contaminated soil adjacent to the study hospital using the double-layer agar overlay method. Phage morphology was assessed by transmission electron microscopy. Host range was determined by cross-streak and spot assay against 50 clinical P. aeruginosa isolates. Phage stability under variable temperature (4 to 70°C) and pH (3 to 11) conditions was evaluated. Three lytic phages designated PAP-ABJ-1, PAP-ABJ-2, and PAP-ABJ-3 were isolated and purified. TEM analysis identified myovirus and podovirus morphologies. Host range testing revealed that PAP-ABJ-1 lysed 74 percent of MDR P. aeruginosa isolates, including isolates resistant to carbapenems and colistin. Phage-antibiotic synergy (PAS) with meropenem was demonstrated for 12 tested combinations. Stability was optimal at 4 to 25°C and pH 6 to 8. These findings establish a foundational phage library against Nigerian MDR P. aeruginosa and support further clinical development of phage-based therapeutic interventions. Keywords: bacteriophage therapy, Pseudomonas aeruginosa, multidrug resistance, phage characterization, Abuja.