Characterization of a bacteriophage infecting drug-resistant Pseudomonas aeruginosa and its application in wastewater treatment.

Bacteriophages are ubiquitous bacterial viruses that specifically infect and lyse host bacteria. They display remarkable diversity in environments ranging from wastewater to the deep sea. Despite their widespread occurrence, many aspects of phage biology and their roles in nature remain poorly understood. In particular, phages that infect Pseudomonas aeruginosa (P. aeruginosa) are especially interesting because of their unique biological features related to host lytic capabilities. Only a limited number of P. aeruginosa phages had been documented in the NCBI database. In this study, we isolated a novel phage (P. aeruginosa phage ϕPAE8) from sewage, which demonstrated effective lytic activity against clinically derived antibiotic-resistant P. aeruginosa strains. ϕPAE8 exhibits advantageous physiological traits, including an extended latent period, a high burst size, and notable stability under various stress conditions such as extreme pH, ethanol exposure, and elevated temperature. These characteristics support its potential use in clinical and environmental applications. Therefore, this study also explored the efficacy of bacteriophage ϕPAE8 in controlling multidrug-resistant P. aeruginosa in a sewage environment. All phage-treated groups showed a significant reduction in the number of P. aeruginosa. The most pronounced effect was observed in the treatment group with an MOI of 50. In this group, the bacterial count decreased significantly and rapidly by approximately 3 log10 CFU/mL within 6 h. Even more surprisingly, we found that the impact of different MOIs on the bactericidal effect may have gradually approximated over time. The results highlight the potential of phage-based approaches as an effective strategy for managing antibiotic-resistant bacteria in complex wastewater systems and provide guidance for subsequent practical applications. In summary, this study details the molecular and genomic characteristics of a novel P. aeruginosa phage, contributing to the understanding of viral diversity. More importantly, it underscores the viability of phage-mediated biocontrol in wastewater management. In contrast to chemical disinfectants that may cause secondary pollution, phage-based strategies provide an environmentally friendly approach. These findings establish a conceptual framework to guide future phage bioengineering efforts aimed at combating antimicrobial-resistant pathogens, facilitating their use in medical and water purification settings.