Bacteriophages: The Natural Combatants to Fight AMR

Viruses infecting eukaryotes are often harmful to their host. The extensive damage done to humankind by the SARS-CoV-2 virus shall remain etched in our collective memory for a long time. However, viruses of bacteria called bacteriophages are hugely beneficial for us and our ecosystem. As with any other of their kind, this group of viruses also requires a living host to propagate, and in the case of bacteriophages, it is a bacterium. Bacteriophages (phages) are also called “bacteria-eaters.” They are the most abundant and ubiquitous biological entity on the planet. By keeping a check on the bacterial population, they play a significant role in maintaining the microbial equilibrium in any ecosystem. The therapeutic purpose of bacteriophages against infectious bacterial pathogens can be traced back to the pre-antibiotic period. However, their exploration as anti-bacterial agents was thwarted after the discovery of antibiotics, except in some East European countries. Now, with the acute rise in antimicrobial resistance (AMR), where most bacterial pathogens have gained resistance to available antibiotics, a rebirth of phage therapy is being observed, and phage-immune system synergies are being investigated. Whole phages (natural and engineered), phage-derived enzymes, and phage–antibiotic combinations are emerging as potential alternatives/complements to antibiotics and, hence, deserve attention not only from researchers, clinicians, and regulatory bodies but also from the common people. The strength of virulent phages as therapeutics lies in their high target-specificity, low or no adverse effects, and abundant presence in nature, which assures a continuous discovery of novel phages and a populated phage pipeline. The spectrum of antibacterial activities of phages is beyond their applications in humans; it is extended to food crops, animals, aquaculture, and poultry farms. Besides, bacteriophages are also effective as biocontrol agents and disinfectants, prophylactics, in microbiome-editing, cancer treatment, etc. Their deployment in technologies such as phage display and drug-delivery systems make them genuinely versatile and promising agents. Hence, advancing our understanding of phage biology and its applications shall reap rich dividends.