Phage Therapy Enhanced by Using Engineered Bacteriophages: A Powerful Antibacterial Tool to Address the Dilemma Posed by Multidrug-Resistant Bacterial Infections

The continuous slowdown in the research and development of new antibiotics and antibiotic overuse have turned the problem of antibacterial resistance into a global public health crisis. As a very promising alternative to multi-drug-resistant bacterial infection, phage therapy is receiving renewed attention. However, the inherent biological limitations of natural phages restrict their extensive clinical application. This review examines how synthetic biology can be harnessed to transform phages and to build the next generation of antibacterial therapies. We outline the main advantages of natural phages, including high host specificity, self-amplification, bactericidal activity and the ability to degrade biofilms. We also point out the bottlenecks of clinical applications of bacteriophages, such as narrow host range, rapid removal in the body and potential genetic safety risks. Moreover, we elaborate on the core synthetic biological tools used to overcome the above limitations, including CRISPR-Cas gene editing, receptor-binding protein reprogramming, functional load delivery and immunogenic regulation, and summarize the recent clinical progress and personalized treatment process. The increasing clinical evidence shows that synthetic biology can effectively overcome the inherent defects of natural bacteriophages, confirming the safety and initial efficacy of bacteriophage therapy. Engineered phages provide a practical strategy to meet the antimicrobial resistance challenge. Clinical applications of such phages will mainly depend on progress in production standardization, regulatory framework construction and scientific and reasonable joint treatment program development.