Bacteriophagesinfect only specific bacteria, so, for research purposes, it is important to coordinate bacteria with their operative bacteriophage.
Some bacteriophages are virulent (reproduce uncontrollably upon infecting the bacterium until they lyse, or burst out of the bacterium, killing it), while others either integrate their genetic material into the DNA of the host or establish themselves as intracellular plasmids, becoming copied with each cell division (these are called prophages).
Bacteriophages are being studied for their potential in fighting bacterialinfection, with uneven success.