SUMMARY Soon after their discovery in the early 20th century, bacteriophages were recognized to have great potential as antimicrobial agents, a potential that has yet to be fully realized. The nascent field of phage therapy was adversely affected by inadequately controlled trials and the discovery of antibiotics. Although the study of phages as anti-infective agents slowed, phages played an important role in the development of molecular biology. In recent years, the increase in multidrug-resistant bacteria has renewed interest in the use of phages as antimicrobial agents. With the wide array of possibilities offered by genetic engineering, these bacterial viruses are being modified to precisely control and detect bacteria and to serve as new sources of antibacterials. In applications that go beyond their antimicrobial activity, phages are also being developed as vehicles for drug delivery and vaccines, as well as for the assembly of new materials. This review highlights advances in techniques used to engineer phages for all of these purposes and discusses existing challenges and opportunities for future work.

Antibiotic resistance is a major public health challenge worldwide, whose implications for global health might be devastating if novel antibacterial strategies are not quickly developed. As natural predators of bacteria, (bacterio)phages may play an essential role in escaping such a dreadful future. The rising problem of antibiotic resistance has revived the interest in phage therapy and important developments have been achieved over the last years. But where do we stand today and what can we expect from phage therapy in the future? This is the question we set to answer in this review. Here, we scour the outcomes of human phage therapy clinical trials and case reports, and address the major barriers that stand in the way of using phages in clinical settings. We particularly address the potential of phage resistance to hinder phage therapy and discuss future avenues to explore the full capacity of phage therapy.

Antimicrobial resistance constitutes one of the major worldwide public health concerns. Bacteria are becoming resistant to the vast majority of antibiotics, and nowadays, a common infection can be fatal. To address this situation, the use of phages for the treatment of bacterial infections has been extensively studied as an alternative therapeutic strategy. Since Pseudomonas aeruginosa is one of the most common causes of health care-associated infections, many studies have reported the in vitro and in vivo antibacterial efficacy of phage therapy against this bacterium. This review collects data of all the P. aeruginosa phages sequenced to date, providing a better understanding about their biodiversity. This review further addresses the in vitro and in vivo results obtained by using phages to treat or prevent P. aeruginosa infections as well as the major hurdles associated with this therapy.