Bacteriophage Types:

In general, there are two types of phages, lytic or lysogenic. Only lytic phages are useful for developing therapeutic phage preparations. Lytic phages multiply inside the bacterial cell and release new phages, thus lysing the host bacterial cell in the process. In contrast, lysogenic phages integrate their DNA into the host bacterial DNA creating a prophage, which can escape and integrate into the DNA of another bacterial cell through transduction. Such phages are inappropriate for use as therapeutic phages because they can foster the transfer of virulence genes, and those mediating resistance to antibiotics, from one bacterium to another.