T4 phage cocktail

A **T4 phage cocktail** is a combination therapy formulation composed of two or more bacteriophages of the T4 type, generally lytic Escherichia coli-infecting viruses, used to treat bacterial infections—most often targeting *Escherichia coli* and related Gram-negative Enterobacteriaceae. T4 is a well-characterized, obligately lytic phage, notable for its ability to specifically infect bacteria via distinct receptor binding proteins. The cocktail's purpose is to broaden antibacterial host range (targeting more strains of *E. coli* or related bacteria) and/or to reduce the risk of bacteria developing resistance by combining phages with non-overlapping mechanisms of resistance escape[1][2]. These cocktails are carefully designed for empirical (“off-the-shelf”) or personalized therapy against multidrug-resistant pathogens[1]. **Mechanism of action:** T4 phages infect susceptible bacteria by adsorbing via tail fibers to specific bacterial surface receptors (e.g., LPS or outer membrane proteins) and injecting their genome, resulting in bacterial lysis by hijacking bacterial machinery, replicating, and releasing progeny. Some cocktails are made by natural selection, while others utilize engineered receptor binding proteins to expand or alter host range[2].

Other names

T4 phage combinationT-4 phage combinationT 4 phage combinationT4 bacteriophage cocktailT-4 bacteriophage cocktailT 4 bacteriophage cocktail