Bacteriophage (Phage)

Bacteriophages, or phages, are viruses that specifically infect and replicate within bacterial hosts [1]. They are the most abundant biological entities on Earth and play a fundamental role in maintaining microbial balance in various environments, including the human body [2]. In clinical applications, lytic phages are utilized as therapeutic agents—a practice known as phage therapy—to combat bacterial infections, particularly those caused by multi-drug resistant (MDR) pathogens [1, 4]. The therapeutic process involves the phage recognizing specific receptors on the bacterial cell surface, injecting its genetic material, and hijacking the host's machinery to produce new virions [3]. This process ultimately leads to the enzymatic lysis and death of the bacterium, releasing new phages to infect adjacent cells [3]. Unlike traditional antibiotics, phages are highly specific to their target bacterial species or strains, which helps preserve the host's commensal microbiome [1]. However, their use faces challenges such as the potential for rapid bacterial resistance and the release of pro-inflammatory endotoxins during bacterial lysis [3, 4]. Additionally, the narrow host range of phages often necessitates the development of personalized phage cocktails to match the specific infecting strain [4]. Despite these challenges, phages represent a promising alternative or adjunct to conventional antibiotics in the face of rising antimicrobial resistance [1].

Other names

PhageBacterial virusProkaryotic virus

Lytic cycle: adsorption to bacterial surface receptors, injection of viral DNA/RNA, replication of viral components, and enzymatic lysis of the bacterial cell wall via endolysins and holins [1, 3].